One solution might be to use ActiveState's PerlApp tool, which turns your Perl applications into executables that can be run on machines without Perl installed. This means that you have to buy ActiveState's $195 Perl Dev Kit.

But, PerlApp doesn't give you absolute security. Anyone who reads the discussion at Security, is it to much to ask? could figure out how to 'decompile' your PerlApp executable and recover the source code. In a lot of cases, PerlApp would give "good enough" security, but anyone who is determined enough could get right through it.

Unfortunately, I don't know of any airtight way to do what you want.