It builds and is installed fine, but when i go to use it in a test script

The compiler may have no problem with it, but perl certainly does. You should test before you install. The problem you're having is that the code you compiled doesn't contain a boot_MappedMaps symbol. That's what (function) DynaLoader calls after loading MappedMaps.so. No one can tell you why it doesn't exist (they can't see the code).