As the ISP is reluctant to help, I am hoping to get to the bottom of the issue by doing their job for them.

As a former hosting provider I have to side with your provider on this one. There is an expectation that if you are doing things on their servers that isn't already shrink wrapped for you that you are on your own to fix issues as they pop up with your scripts.

As someone who has in the past been frustrated by a provider's willingness to update their woefully inadequate Perl module selection I no longer use shared hosting. Consider getting yourself on a VPS. It's more responsibility in terms of keeping things running, but you get to control your world. There are lots of providers out there that provide Windows and Linux VPS plans. If you'd like a recommendation msg me privately.