Note that this didn't answer the question I had about the module. I already knew that "nothing" was returned for failure. What would be nice to know, is how to get the failure reason. This is often hard to find in the documentation so I often just look at the source... which is conveniently made available by http://search.cpan.org/... except that this module isn't on CPAN and I suspect the author doesn't make the source available anywhere else (this is certainly the case for some modules from this author). So the next step might be "try it and see" if $^E works for that, but I avoid installing non-CPAN modules so I won't (the original problem was solved anyway).