I've had similar issues with several epub books. I think that the zlib library used by python (and maybe Calibre?) is having trouble unzipping certain epubs.
I was able to fix the issue by unzipping the original file using the built in decompression program in OSX (rename the file from mybook.epub to mybook.zip and double click on it). I forget what I used in Windows... it might have been the built in program, or maybe WinZip. I avoided using the command line unzip
which uses the zlib library.
Then I just rezipped it using the command line zip
(or, on Windows, the cygwin version of zip
cd "epub directory"
zip -X0 "full path to new epub file" mimetype
zip -rDX9 "full path to new epub file" * -x "*.DS_Store" -x mimetype
This should be done before using DRM disinfection.
Credit goes to pdurrant at http://www.mobileread.com/forums/showthread.php?t=55681
for the command line wizardry.
(I'm not sure how to zip it in Windows without cygwin.)
After rezipping it worked fine.