To quote perldiag:

Insecure dependency in %s
           (F) You tried to do something that the tainting mechanism didn’t like.  The tainting mecha‐
           nism is turned on when you’re running setuid or setgid, or when you specify -T to turn it on
           explicitly.  The tainting mechanism labels all data that’s derived directly or indirectly
           from the user, who is considered to be unworthy of your trust.  If any such data is used in a
           "dangerous" operation, you get this error.  See perlsec for more information.

I don't do a lot with tainting, but if memory serves, you have to explicitly set stuff like $ENV{PATH} to make sure that someone didn't sneak a directory in there that has a command in there called "env" that launches nukes or something. perlsec is recommended reading.