What platform are you running on? You need to be careful, because sometimes if perl is built using a different compiler than packages you are trying to install, there can be problems.
I've actually only run across this issue on solaris, where perl was installed with solaris from the vendor. But we didnt buy their C++ compiler. So, to get some perl modules to run correctly, we had to recompile perl using gcc, then complie the packages.

You may not be in this situation, but i thought i'd throw out the possibility.