D'ho, lucky me that I put the big "untested code" :) I was convinced that the substr function would return undef if the string was empty (like the middle element in "ciccio.exe,,pallo.dll"), but it is simply the empty string.

I could agree on the second correction, but only on a robustness ground that seems not necessary in this case. Anyway, better being overprotective, especially when it's cheap and helps building the right attitude.