Perl SheBang Syntax
If you are using PSA correctly then IIS should be installed.
Right Click the desired domain
Click Properties
Click The Home Directory Tab
Click Configure
Click Add
Browse to C:\Program Files\Swsoft\Plesk\Perl\bin
Select either Perl.exe or PerlIIS.dll
Click OK
Rename Program Files to Progra~1 in the directory window
Use this same method for .pl, .plx and .cgi files
I strongly recommend you use the .dll filter versus the executable for speed.
In your code, the correct syntax is:
#!Perl
Hope this helped.