File not saved

[1N.]

I have downloaded Revit( Architecture, MEP, Structural) 2011 and activated the products. Latest server packs are applied too...Revit keeps telling me - when I try to save a NEW file that: "the file .... was saved in a later version of Revit and cannot be retrieved in this version" which I cannot understand becasue I am in the latest version. Even trying to save sample files, from the newly installed Revit, it tells me the same.However I can open 2010 files and save them without any problems.

[Elmo]

You might need to do a uninstall re-install. Sounds a little strange that this would be happening especially if you have applied the latest service packs.