Installing a separate perl using something like perlbrew is the simplest way to go, as suggested by kcott in 11135780. That assumes you can get past the lack of internet access, although I assume others have encountered and and solved that issue previously so there will be previous experiences you can draw on.
Another option is to use local::lib to keep your module installs out of the way of the system package tree.
Another consideration is how you installed the local modules from metacpan. If you have no direct internet access on that box (as noted in 11135802) then I assume you downloaded the tarballs manually and transferred them across? Did you run the module tests? Did they fail and you then force installed? Did you skip the tests? I would expect the module tests would throw issues in cases like this.
And don't forget to check the value of @INC. It could be that your modules installed correctly, but if .../perl/site/lib is listed after .../perl/lib then issues like this can occur.