Apologies, I don't have the errors anymore. When I try doing install Compress::Zlib it says it's up to date, and if I force install all tests (aside from ones it skips) are successful. I'm really confused as to why I get Can't locate Compress/Zlib.pm in @INC after installing it with CPAN.
I don't know how to remove modules installed with CPAN, otherwise I would reinstall them for the error messages.