Unfortunately there isn't much that can be done. I've had issue's with my Epic and SD cards and this is my 3rd phone and SD card but I continue to have the same problem with my SD card being fine in the phone but won't always load the files onto the screen. I have to constantly reboot the phone until everything shows up and everything works fine but it is a PIA to have to go through. Sprint is aware of the SD card problems but they don't have the answer. Don't listen to anything they try to tell you because it will usually be, "Do a hard reset on the phone", "Take the battery out and reboot the phone", "Take it to a Sprint service center", or some other lame answer. The problem is there is an issue with the phone and the SD cards but they don't know what to do about it. I'm hoping the problem will be fixed with the OTA Gingerbread update which should happen in November given they aren't still having error issue's with it. Samsung won't do anything either so we'll have to just wait and see if Gingerbread fixes it. If not then it's definitely a hardware issue and I'm trading my Epic in for something other than Samsung.
Jim