magestatue.nif - Had no valid material set
whvalunstrad11.nif - Was set to Metal instead of Dirt, and Invalid instead of Stone
whvalunstrad13.nif - Was set to Metal instead of Dirt, and Invalid instead of Stone
whvalunstrad14.nif - Was set to Metal instead of Dirt, and Invalid instead of Stone
whvalunstrad15.nif - Was set to Metal instead of Dirt, and Invalid instead of Stone
whframewood.nif - Was set to Stone instead of Wood
whdoorfrontgate.nif - Had no valid material set
whgrayquarterdoor01.nif - Had no valid material set
whintmetalarchdoor.nif - Had no valid material set
whmetalarchdoor.nif - Had no valid material set
whcastledoorentrance.nif - Had no valid material set
wharenadoor.nif - Had no valid material set
I doubt the last one is actually used in-game but I fixed it anyways and leave it up to you whether or not to include it in USKP.
Fixed meshes: <a href="https://dl.dropbox.com/u/41720073/skyrim/materialfixes1.rar">http://dl.dropbox.com/u/41720073/skyrim/materialfixes1.rar</a>