No, these aren't the only issues involved. Not all modules are pure Perl, many require compilation. Many modules require further cpan based dependancies, external libraries or tools and so on which require their own installtion procedure. In such cases simply copying files and editing their permissions isn't going to work. cpan, cpanp and cpanm take care of this for you. Module documentation should cover the basics of installation.

Agreed it is far from the only potential issue, I only raised that single suggestion as I thought it was the most likely cause of the error as described. I expect other problems related to incorrect installation will give further errors when that one is resolved.