Hello,
If you're running with the ActiveState perl, I strongly suggest that you check the documentation bundled with the distribution, epecially the section Web Server Config

Here's the procedure to follow (from the top off my head, there may be some mistakes)

1. Open the IIS administration console
2. Select your cgi-bin directory
3. Open the Configuration properties
4. There should be something like Application Map
5. Add ".pl" + your perl executable to the Map
6. You're done! You may need to restart IIS

Any correction, precisions welcomed...

<kbd>--
PerlMonger::Paris(http => 'paris.pm.org');</kbd>