I don't think that Apache lets you avoid the "hashbang" line. This is likely a security feature so that only the explicit version of the Perl interpreter that you want gets invoked.

How do you print the Perl version? I find it hard to believe that any current XAMPP distribution distributes Perl 5.005_05 or anything from before the three-point-versions.

As a third question, what did you try to install Modern::Perl, and how did it fail?