The Perl you run does not seem to be the Perl you want.

You need to find out which Perl version t-prot invokes, and how. A most likely candidate is to look at the first line of t-prot. If it starts with something like #!/System/bin/perl (or whatever OSX uses as path names), you could try to change that to point to the Perl you want to use. I recommend making a backup first.