No, it's not wrong at all. Actually, it's more common than naught. Think of this message as the small price we pay to avoid spelling errors.

my $temp = $CONFIG::foo;

Unless you use $temp in more than one spot, you'll not avoid the message. Think about it.

This issue has been addressed a multitude of times. Check out this link and go from there. Good luck with it.

If things get any worse, I'll have to ask you to stop helping me.