Message1502

And yet, oddly enough, passing the command as a list of strings works fine

GOOD:
jython.bat -c "import os ; os.system(['\\Program Files\\WinZip\\WINZIP32.EXE', 'FOO.ZIP'])"

BAD:
jython.bat -c "import os ; os.system(chr(34) + '\\Program Files\\WinZip\\WINZIP32.EXE' + chr(34) + ' FOO.ZIP')"

BTW a print shellCmd statement in javashell.py just before line 61 displays this just before the exception:
['cmd', '/c', '"\\Program Files\\WinZip\\WINZIP32.EXE" FOO.ZIP']