I'm not 100% sure about this, but I always have my configuration modules separate from handler modules. The docs show this in the examples and could be the problem.

So you'd setup a dir_browse::parameters module that you would PerlLoadModule in and then your existing dir_browse::dir_browse module with the handler as is, except you'd change the __PACKAGE__ in get_config() to 'dir_browse::parameters'. And just PerlModule that one in.

Hope this helps...