lol! Had the same problem, but I managed to find a 'ring ring' MIDI tone through extensive searching - if anyone wants the file, I'll stick it somewhere and post a URL (you'll need some s/w and IR/cable to download it to phone though - see Nokia website).
you probably need a data cable or an infra red connection to your pc and midi software, you can get the software from the nokia site, im sure you can anyway because thats where i got my 7210 software