Thanks all

I found the problem late last night and looks like Corion had picked the root cause. The constructor of the class giving trouble was creating an object in $self that could not be serialized, hence the problem when Resub tried to capture @_ that would be passed into the real sub.

As there was no need for the ref to it to be in $self, I removed it and replaced it with a lazy "getter", now all is well.

Re the perlcc question, my app (27,351 LOC in all modules) uses Tk and I distribute binaries for Win32, Unix, and OSX using ActiveState perlapp to create them (plus the source which I think nobody looks at). Sadly, ActiveState dropped Tk after 5.8, so I HAVE to use 5.8.x. Them's the breaks...