Fist off, welcome to the forums. Yes some( me included ) get irretated on some questions. The answer to your question isn't that obvious though, so that gives you the free pass for posting this in the wrong place(
Instead of 3dchat...this is for ingame work thats completed)
What it is, you have a missing mesh. Exactly what mesh is missing, no one knows. This can happen offten due to:
* Packs with errors that you've tried to install.
* Incorectly installing packs.
* Building a map then later unistalling a pack and trying to load the old map.
Sorry to say that basically this error boils down to user error 95% of the time. Finding the offending mesh can at times be problematic if you have a very large game.
Theres not really much help anyone can offer.
Good luck,
Loc
Read the stickies man...learn where to post......