Index: src/org/python/core/packagecache/PathPackageManager.java
===================================================================
--- src/org/python/core/packagecache/PathPackageManager.java	(revision 6093)
+++ src/org/python/core/packagecache/PathPackageManager.java	(working copy)
@@ -41,20 +41,24 @@
             String dir = path.pyget(i).__str__().toString();
 
             File f = new RelativeFile(dir, child);
-            if (f.isDirectory() && imp.caseok(f, name)) {
-                /*
-                 * Figure out if we have a directory a mixture of python and
-                 * java or just an empty directory (which means Java) or a
-                 * directory with only Python source (which means Python).
-                 */
-                PackageExistsFileFilter m = new PackageExistsFileFilter();
-                f.listFiles(m);
-                boolean exists = m.packageExists();
-                if (exists) {
-                    Py.writeComment("import", "java package as '"
-                            + f.getAbsolutePath() + "'");
+            try {
+                if (f.isDirectory() && imp.caseok(f, name)) {
+                    /*
+                     * Figure out if we have a directory a mixture of python and
+                     * java or just an empty directory (which means Java) or a
+                     * directory with only Python source (which means Python).
+                     */
+                    PackageExistsFileFilter m = new PackageExistsFileFilter();
+                    f.listFiles(m);
+                    boolean exists = m.packageExists();
+                    if (exists) {
+                        Py.writeComment("import", "java package as '"
+                                + f.getAbsolutePath() + "'");
+                    }
+                    return exists;
                 }
-                return exists;
+            } catch (SecurityException se) {
+                return false;
             }
         }
         return false;
Index: src/org/python/core/imp.java
===================================================================
--- src/org/python/core/imp.java	(revision 6093)
+++ src/org/python/core/imp.java	(working copy)
@@ -194,6 +194,9 @@
         }
         FileOutputStream fop = null;
         try {
+            SecurityManager man = System.getSecurityManager();
+            if (man != null)
+                man.checkWrite(compiledFilename);
             fop = new FileOutputStream(compiledFilename);
             fop.write(compiledSource);
             fop.close();
@@ -203,6 +206,11 @@
             Py.writeDebug(IMPORT_LOG, "Unable to write to source cache file '"
                     + compiledFilename + "' due to " + exc);
             return null;
+        } catch(SecurityException exc) {
+            // If we can't write the cache file, just log and continue
+            Py.writeDebug(IMPORT_LOG, "Unable to write to source cache file '"
+                    + compiledFilename + "' due to " + exc);
+            return null;
         } finally {
             if(fop != null) {
                 try {
@@ -443,8 +451,12 @@
         File sourceFile = new File(dir, sourceName);
         File compiledFile = new File(dir, compiledName);
 
-        boolean pkg = dir.isDirectory() && caseok(dir, name) && (sourceFile.isFile()
+        boolean pkg = false;
+        try {
+            pkg = dir.isDirectory() && caseok(dir, name) && (sourceFile.isFile()
                                                                  || compiledFile.isFile());
+        } catch (SecurityException e) {
+        }
         if (!pkg) {
             Py.writeDebug(IMPORT_LOG, "trying source " + dir.getPath());
             sourceName = name + ".py";
@@ -459,28 +471,33 @@
             m.__dict__.__setitem__("__path__", new PyList(new PyObject[] {filename}));
         }
 
-        if (sourceFile.isFile() && caseok(sourceFile, sourceName)) {
-            long pyTime = sourceFile.lastModified();
-            if (compiledFile.isFile() && caseok(compiledFile, compiledName)) {
-                Py.writeDebug(IMPORT_LOG, "trying precompiled " + compiledFile.getPath());
-                long classTime = compiledFile.lastModified();
-                if (classTime >= pyTime) {
-                    PyObject ret = createFromPyClass(modName, makeStream(compiledFile), true,
-                                                     displaySourceName, displayCompiledName, pyTime);
-                    if (ret != null) {
-                        return ret;
+        try {
+            if (sourceFile.isFile() && caseok(sourceFile, sourceName)) {
+                long pyTime = sourceFile.lastModified();
+                if (compiledFile.isFile() && caseok(compiledFile, compiledName)) {
+                    Py.writeDebug(IMPORT_LOG, "trying precompiled " + compiledFile.getPath());
+                    long classTime = compiledFile.lastModified();
+                    if (classTime >= pyTime) {
+                        PyObject ret = createFromPyClass(modName, makeStream(compiledFile), true,
+                                                         displaySourceName, displayCompiledName, pyTime);
+                        if (ret != null) {
+                            return ret;
+                        }
                     }
+                    return createFromSource(modName, makeStream(sourceFile), displaySourceName,
+                                            compiledFile.getPath());
                 }
+                return createFromSource(modName, makeStream(sourceFile), displaySourceName,
+                                        compiledFile.getPath(), pyTime);
             }
-            return createFromSource(modName, makeStream(sourceFile), displaySourceName,
-                                    compiledFile.getPath(), pyTime);
-        }
 
-        // If no source, try loading precompiled
-        Py.writeDebug(IMPORT_LOG, "trying precompiled with no source " + compiledFile.getPath());
-        if (compiledFile.isFile() && caseok(compiledFile, compiledName)) {
-            return createFromPyClass(modName, makeStream(compiledFile), true, displaySourceName,
-                                     displayCompiledName);
+            // If no source, try loading precompiled
+            Py.writeDebug(IMPORT_LOG, "trying precompiled with no source " + compiledFile.getPath());
+            if (compiledFile.isFile() && caseok(compiledFile, compiledName)) {
+                return createFromPyClass(modName, makeStream(compiledFile), true, displaySourceName,
+                                         displayCompiledName);
+            }
+        } catch (SecurityException e) {
         }
         return null;
     }
Index: src/org/python/core/SyspathJavaLoader.java
===================================================================
--- src/org/python/core/SyspathJavaLoader.java	(revision 6093)
+++ src/org/python/core/SyspathJavaLoader.java	(working copy)
@@ -112,6 +112,8 @@
         try {
             return Class.forName(name, true, ClassLoader.getSystemClassLoader());
         } catch(ClassNotFoundException e) {}
+        catch (SecurityException se) {
+        }
 
         Class<?> c = findLoadedClass(name);
         if(c != null) {
@@ -143,11 +145,13 @@
                 if (file == null) {
                     continue;
                 }
-                size = (int)file.length();
                 try {
+                    size = (int)file.length();
                     fis = new FileInputStream(file);
                 } catch (FileNotFoundException e) {
                     continue;
+                } catch(SecurityException e) {
+                    continue;
                 }
             }
             try {
Index: src/org/python/core/PyTraceback.java
===================================================================
--- src/org/python/core/PyTraceback.java	(revision 6093)
+++ src/org/python/core/PyTraceback.java	(working copy)
@@ -50,9 +50,13 @@
      */
     private String getLine(String filename, int lineno) {
         RelativeFile file = new RelativeFile(filename);
-        if (!file.isFile() || !file.canRead()) {
-            // XXX: We should run through sys.path until the filename is found
-            return null;
+        try {
+            if (!file.isFile() || !file.canRead()) {
+                // XXX: We should run through sys.path until the filename is found
+                return null;
+            }
+        } catch (SecurityException e) {
+            return null;  // If we don't have read access to the file, return null
         }
 
         PyFile pyFile;
Index: src/org/python/core/BytecodeLoader.java
===================================================================
--- src/org/python/core/BytecodeLoader.java	(revision 6093)
+++ src/org/python/core/BytecodeLoader.java	(working copy)
@@ -1,7 +1,8 @@
 // Copyright (c) Corporation for National Research Initiatives
 package org.python.core;
 
-import java.security.SecureClassLoader;
+import java.net.URL;
+import java.net.URLClassLoader;
 import java.util.List;
 
 import org.objectweb.asm.ClassReader;
@@ -30,7 +31,8 @@
                 if (cur != null) {
                     loader.addParent(cur);
                 }
-            } catch (SecurityException e) {}
+            } catch (SecurityException e) {
+            }
         }
         return loader.loadClassFromBytes(name, data);
     }
@@ -71,11 +73,12 @@
         }
     }
 
-    public static class Loader extends SecureClassLoader {
+    public static class Loader extends URLClassLoader {
 
         private List<ClassLoader> parents = Generic.list();
 
         public Loader() {
+            super(new URL[0]);
             parents.add(imp.getSyspathJavaLoader());
         }
 
@@ -115,7 +118,6 @@
             }
             Class<?> c = defineClass(name, data, 0, data.length, getClass().getProtectionDomain());
             resolveClass(c);
-            Compiler.compileClass(c);
             return c;
         }
     }
Index: src/org/python/modules/zipimport/zipimporter.java
===================================================================
--- src/org/python/modules/zipimport/zipimporter.java	(revision 6093)
+++ src/org/python/modules/zipimport/zipimporter.java	(working copy)
@@ -91,11 +91,12 @@
         prefix = "";
         while (true) {
             File fullPathFile = new File(sys.getPath(pathFile.getPath()));
-            if (fullPathFile.exists()) {
-                if (fullPathFile.isFile()) {
-                    archive = pathFile.getPath();
-                }
-                break;
+            try {
+              if (fullPathFile.isFile()) {
+                  archive = pathFile.getPath();
+                  break;
+              }
+            } catch (SecurityException se) {
             }
 
             // back up one path element