Your zip file is corrupted or you unpacked it wrong, the exe file should not be zero.

If you never got an error unpacking, it's likely the file was bad to begin with. Got to the original site and re-download. Make sure you delete the old zip file and the unpacked versions before. IE resumes file is file exists. Also, it could be cached.

Clean up cache, delete the zip and the extracted version and try again. the \run\>john-386.exe command should have worked if the exe was there.

Oh, and, watch for antivirus. John is a cracker so the AV could kill it, thus resulting in a zero file.