I have looked at past discussions about this and previous solutions don't seem to work.  When I try to create a new sheet in a drawing I get the message "The sheet format could not be located" and  if I click OK then browse it shows me the format file I want.  Double click on it and all is well.  Is it broken in 2010?  I know it used to work providing I had the drwdot and a slddrt in the same folder.