When my main character gets enough xp to gain a level, is there a reason Tumble isn't on the list of skills? My poor old monk could use the extra AC from the tumble bonus.

That's definitely not a server-sided bug! It should always show up, and if it doesn't your NwN doesn't seem to recognize the SoU/HoTU expansions.

It's probably not showing up because you haven't taken any skills in the skill. Tumble is a skill that requires training. When you level up, it should be available for you to choose.

SInce I created this character, Tumble had never been in my list of skillls to take. I leveled a couple nights ago, and it was there for the first time, I just assumed one of you DM's fixed it, so even though I am behind on that skill from where I should be, I have the opportunity to make it up now. As for NWN not recognizing the expansions, I created another character and Tumble was there from the time I built that one, as it should be. Just one of the strange things that can happen, I guess.

This is a client-side issue, as the EFU server has no modifications to the skills.2da file. It also appears to be cleared up.

It could have been the result of any number of things, from playing on a server/module with hakpaks prior to playing EFU (thus loading that server/module's custom content) to placing some odd files in your override folder.