There are a few issues here. Not every module can simply be copied into the right place. Some modules have external dependencies (as well as other cpan dependencies) which may not be satisfied. You haven't mentioned which modules you're trying to install.
My suggestion would be to create a mini CPAN mirror on a system which does have internet access (for example, the one you used to post this question) and transfer it to the system without internet access, and configure cpan accordingly. minicpan makes this easy to do. See also Yes, even you can use CPAN.