Hehe, you're missing a mesh, pretty obvious
You'll need to http://sites.google.com/site/oblivionpoinfo/troubleshooting/postlo to get more specific details...but fiiiiirrrrst:
1.) http://sites.google.com/site/oblivionpoinfo/troubleshooting/cps/yellow-wtf-meshes
2.) Download http://www.tesnexus.com/downloads/file.php?id=16704 to find what specific mod is looking for that pesky mesh. Should give you a good idea where to start anyway.
I really would recommend at least http://sites.google.com/site/oblivionpoinfo/index with the basic sections of Tomlong's site, as she has compiled an excellent array of information into this easy to read (yes, hun, it's pretty damn good
) site.
EDIT: Pesky url tags :shakefist: