No, the only scripts ever executed are dashboard.php and ubbthreads.php, only the admin folder should be 755, add there is no editor for admin pages, so it doesn't need to be 777 or the files on it anything but 644.
I followed the upgrade URL above and it states
Linux, Unix, and Mac Servers:
• admin/ folder: set permissions to 777
• files within the admin/ folder: set permissions to 666
Setting admin folder back to 755 and still crashes for dashboard.php
