Just found that betterzip (1.7.2) seems to have an issue with zipfiles whose name contains the character '$'. Issue is betterzip always asks for a password when opening the file (with doubleclick) even if the zipfile is not password protected.

I can send a zipfile that replicates the bug or you can:
1) create with betterzip a new zipfile named test.zip with no password
2) rename with finder the file test.zip to test$test.zip
3) open test$test.zip and you will be asked for a password even if the zipfile is not password protected.

Also note that betterzip dos not let you save the zipfile with a filename containing the character '$'

Paolo