Do you use the perl interpreter installed by your OS or did you compile it yourself?

Yes, that could be part of the problem.
It looks to me that /usr/bin/perl is being invoked to run "test.pl" ... I don't know which perl could be running "perlcritic".

One other thing I notice is the OP doesn't explicitly state that the POSIX module does, in fact, export "setsid".
For example, on Windows, "setsid" is not implemented, let alone exported.
However, Perl::Critic doesn't build for me on Windows, so I don't get to see how the command perlcritic --stern ./test.pl reacts to that "test.pl" file on WIndows.

Cheers,
Rob