It's worth pointing out that you shouldn't use variables in system calls without knowing for sure what the variables contain. If you aren't positive that what's in $ep is safe, you are taking a huge risk.

You should read the section on Taint mode and @INC in perlsec (and, in fact, all of perlsec is good reading) before letting that line into a public/production environment.

Yeah, I'm paranoid -- once bitten, twice shy and all that.