What exactly is your question? You're not using taint checking, and you're not doing anything that would trigger
a taint check anyway. It's also not code that could trigger
the message you describe, and there's no taint checking
turned on.
You can run Perl with taint checking switched on, with IIS, though I will admit it's not as easy as with a proper web server such as Apache - which runs very well on NT systems.
A long time ago when forced to use NT/IIS I ran into the same problem, and it's normal work-around - Taint with Perl on NT/IIS.