Many apologies for the (lengthy) delay in response to this. Thanks for all your suggestions.

This panned out as follows: The pp_autolink suggestion was a good call - thanks for pointing that out. After using this it still spewed out an error message (this time related to trying to *write* to a file in the temp directory) but it seemed to catch the error and the process continued to execute without other issues. I was able to suppress that error message by adding a hack to Archive::Zip::Member to bypass the write. This solved the immediate issue.

However I have inherited a whole batch of these scripts which were previously compiled on windows, but now have modification requirements. One thing I wanted to do was optimise some of the download routines by getting them to run in parallel. Again this seemed to work fine with the interpreter, but the compiled version definitely did not want to play ball. So finally I've managed to persuade my client to move the bulk of the processes onto a server, and just have a minimal windows app interface with an API endpoint which does the dirty work. This approach seems to be working a lot better: my client appears happy, and the missing clumps of hair are slowly growing back :)

I should say, the --clean suggestion was also a good one - I'd not noticed that flag existed. Unfortunately it didn't seem to make a difference in this particular case, but it was a good idea - thanks for pointing it out.