Maybe...
"not enough storage is available": how much free disk space do you have?
"the file is a compression bomb": you can change the sensibility of avast into avast4.ini file (click on Settings in my signature). There is some explanation there too.
"CAB archive is corrupted" and "ZIP file is corrupted": the file has an internal problem and cannot be scanned by avast.
"the file is password protected": avast can't scan files that are password protected, it doesn't know the password. There are many legitimate reasons why a file was password protected. For intance, the ones you're talking about. Lavasoft stores its data in a password-protected ZIP archives (to prevent other similar tools from messing up with them). It's really nothing to worry about - it's normal.
