WordPress MU

I think something may be wrong in the .htaccess file that creates issues with (or withut) trailing slashes. As an example if i try and go to http://wugga.com/invite/ (notice the final /) I get to the correct page but if i try and got to http://wugga.com/invite (no trailing /) Apache adds a / to the end and rewrite does something, I'm not sure in what order, and I end up with http://wugga.com//invite/ (two /'s after the domain and one at the end) which results in a Not Found error page telling me that "The requested URL //invite/ was not found on this server."

I think this is part of the problem discussed here http://mu.wordpress.org/forums/topic/268

This is not necesarily related to the invite system I just choose that link as an example. The proble seems to be between Apache and mod_rewrite both trying to add a slash.

for the final / try /? instead. (in you .htaccess of course)
the / at the beginning shouldn't do any harm, normally... but in your's it's different. maybe there's another place in your .htaccess where a /? should be.