I think when launching Perl, it's best to either set up $ENV{PATH} so that only one perl.exe is found, or to be (very) explicit in specifying which perl.exe to use.

For example the following will always launch Strawberry Perl:

c:\strawberry\perl\bin\perl.exe myscript.pl
[download]

Personally, I have a file path.cmd in each directory containing a Perl installation, which sets up $ENV{PATH} so that only the perl.exe below it is found:

@echo off
SET BASE=%~dp0
path %BASE%\perl\bin;%BASE%\mingw\bin;%BASE%\dmake\bin;%PATH%
[download]