Although single stepping gives the 100 levels message, setting a breakpoint on AUTOLOAD catches the problem and gives you enough information about what is going on. I've encountered this one myself, when I was doing "creative" things with AUTOLOAD.
A more interesting and challenging problem is what happens when there is inheritance. Perl scans the @ISA tree and will call a sub there if it finds one. If there was no sub in the whole tree of name spaces, it then scans the @ISA tree for an AUTOLOAD sub. Have a peep inside the source code of my module Devel::Leak::Object for a convoluted example.
Oh Lord, won’t you burn me a Knoppix CD ?
My friends all rate Windows, I must disagree.
Your powers of persuasion will set them all free,
So oh Lord, won’t you burn me a Knoppix CD ?
(Missquoting Janis Joplin)