I have this issue too with the GB update. I have ringtones on my sd card that I've assigned to a few people.
You might want to try placing your personalized ringtones into:
/system/media/audio/ringtones/<filename.mp3>
and...
/system/media/audio/notifications/<filename.mp3>
You might have to restart to get the phone to read/index the SD card again.
I say this becuase this is where my factoy ringtones are located on my OTA GB stock TBolt. I've seen threads here that when you assign personal ringtones to secific people, they must reside it whatever the default factory ringtone directlory is. For plain non-personalized ringtones, (i.e. text msg, incoming call, email, etc.), they can be anywhere on the SD card.
If you're running a custom ROM, check where the factory ringtones are and place them there.
OTOH, if you can't access the directories above, try: /sdcard/media/ringtones/<filename.mp3> or /sdcard/media/notifications/<filename.mp3>
Not speaking from experience here, but it does seem like if you can get your ringtones into the phone's default directory it should be able to find it. Or, into the equivilent SD card directory. If you've loaded a Market app with ringtones, whereever that app stores ringtones shluld also be found.
Just some thoughts.
-Frank