It's possible 6.1.0.3 isn't compatibile with that version of Perl (where the test script may execute it's possible that other items in the script itself rely on outdated items that may have been depreciated in newer versions of Perl); since the v6 series is well past EoL and the 6.1 part of it would have been quite a long time ago... Is there any particular reason you want to run 6.1? There will be several security issues with running that version of an end of life build...
And yes, the shebang line will always have to point to the location of Perl in order for Perl to run a script.
