ROKR E6

ROKR E6 is no doubt the best I ever owned, but I am having a few problems in finding a nice video player for it. Real Player is not playing MP4 videos encoded @ 320 240 resolution, properly. Its stuttering a lot, can you please help?
Also, The phone hangs if a sms comes in while real player is playing a file from SD card.. no problems while playing from phone memory.