This is probably the winfilecache corruption issue. I have found that if I rename my floater directory to something else, then open Dreamweaver... then close dreamweaver and rename the directory back to floaters it will clear out floater errors that persist even when deleting the filecache.dat file.
Either way it is probably a phantom error that can be solved by clearing the filecache.dat file and/or playing with getting the floaters reset.