Reaper/ASIO crashes with omnisphere

When i use omnisphere, it takes about 10 secs to load, suddelny i get a message that the asio stopped working. I use asio ux1 with m pod ux1 soundcard. I need to reebot the comuter to make it work again. Asio 4all still works, but i cant hear my wav fles when i use it. My computer has 8 gigs of ram and i5 proceessor and is brand new. (Is there a way i can make a midi file into a wav file, in reaper, so after i have recorded with omnisphere, i can close the program)?