in reply to namespace::clean and "Unknown Error"
5.10 broke just about any code written prior that looks into a package's namespace. That seems likely to be part of the problem here.
For the sake of saving memory, 5.10 causes code that expects (as has always been the case) for package symbol tables to only contain 'globs' to die with the fatal error "Not a glob reference at". This even broke the 5.10 debugger.
I think this optimization was included too cavalierly and it should become optional (an environment variable makes for an easy control mechanism) for 5.10.1.