One, square brackets are significant to glob just as they are to most UNIX shells (e.g. foo[abc] meaning match any of the files fooa, foob, or fooc), so you'll need to escape them with backslashes. Two, see File::Find or File::Find::Rule rather than reinventing the wheel.

Addendum: And you should test if something's a directory (see -d in perldoc -f -X) before trying to recurse down into it anyway.