I think Vista has this option somewhere called "show legacy files" or something... unfortunately I can't remember what exactly it's called or where to get to it...
As for the invalid empire name, that seems really strange... you don't have any sort of punctuation or other funky characters in your empire name, do you? Or is the name really long? You shouldn't have to enter the name of the file; the empire name you enter should be Empire Name Empire Type (e.g. "Phong Confederacy"), but it really shouldn't even matter what you enter there, since it's only used for display on PBW... you could put "Fred Astaire" for all PBW cares
