Other than $RCfile et. al not being passed by reference (as was already mentioned), I ran your code and got no errors.

I'm running Getopt::Long version 2.25 on ActiveState perl v5.6.1. Perhaps this is a newer/older(?) version of Getopt::Long than you're running...?

bbfu
Seasons don't fear The Reaper.
Nor do the wind, the sun, and the rain.
We can be like they are.