i think someone has macBinary encoded the files TWICE to alot of the archives
i have noticed that i had to rename the file i downloaded first because there is a file of the SAME NAME inside of itself.. and when you drag to stuffit expander it causes a filename collision and stops the extraction and you end up with file of the same name with a "1" on the end but the extraction sequence does not complete
try renaming the file first before extracting it to prevent the filename collision,
again this is just a guess, based on what ive experienced. i may be way off on whats happening to you.. or it may help.
good lluck