i had that exact same problem! after 2 hrs of tooing and fro-ing i realised that the first time i downloaded the software for some reason i wasnt given the r4.dat file. this is what was missing so i downloaded it a second time and now i can open the r4, what icannot open now is the games ive downloaded! all i get are 2 completely white screens!!! i hope this is worth it in the end cos im starting to get a headache!