In the library I use there is only combinatorics.pm, I also have a combinatorics directory that contains an bundle, and a bs file which i dont refer to, this directory is located in the place it usually installs the .pm file:S, I hope this helps for clarity
You will not be able to just copy a module with a compiled c component into your 'lib' and expect it to work. If you want to try and outsmart the Perl Dynaloader, read perldoc Dynaloader and possibly set @dl_library_path.