Ok, I'm busy today with other things, I'll try to look at this tomorrow morning (eastern time) if I can. I'll let you know soonest what I find.
So, I think I discovered the issue. With one of my source forums, the .htaccess was set to:
<Files *>
Order Allow,Deny
Deny from All
</Files>
And the other forum didn't even have an htaccess file. When I created one in the forum that was missing on there and changed the 'Deny' to 'Allow,' it worked!
Rejoice!
Nice find, but really a PITA
