You are able to give back to CPAN, maybe not perl code but that's not all there is.

For example, what if you find a bug in a module? Or something you believe is a bug? You can always mail the module maintainer and inform him about it. After which he can look at it and fix the bug.

You could also try to create a little test-case/script and send it along with your bug report so that the maintainer can easily check if the bug is fixed and perhaps include the test in the distribution. (To make sure the bug is fixed once and for all.)

Another thing you might be able to do is mail the module maintainer about a unclear statement that is too unclear in the docs. You said it yourself, you are not a programmer, perhaps the programmer who wrote it considers it to be too obvious to add a bigger explanation?. Perhaps you don't understand all the constructs used in the module's documentation, perhaps the examples need to be easier, ...

If you do that then you are indeed not contributing code or modules to CPAN but you certainly are contributing to CPAN (IMHO).