I suppose it may depend on your phone and version of Android, but I was having the same issue tonight. I had my ringtones in the sdcard, under usbstorage/My Ringtones and none of them would work. So after reading a bunch of threads on this I moved them to usbstorage/media/audio/ringtones.....didn't work....then moved them to usbstorage/media/ringtones.....didn't work.....then I noticed I've got a folder under the root of sdcard called Sounds.....so the path now looks like /sdcard/sounds/ringtones. And it works fine now. I have a Sprint Epic 4G Touch (Galaxy SII), with the latest update, gingerbread 2.3.6. So for anyone having this problem, see if you have a folder called Sounds in your built in sdcard (not an external) and try moving the ringtones folder there.