I have a bunch of ringtones on my memory card and I just put it into the Curve from my LG phone.
I go to set a ringtone for a particular person and the ringtone title shows up but there is a 0.00 next to it. SO, I waited and tried again after 10 minutes and then all of the songs were there where they showed the amount of memory that they are taking up. I set a particular person s ringtone and then went back to it....they're gone again!!!
Funny, I have ring tones in my media card and I can assign ring tones to different callers with no problem. Maybe corrupt media card? If so, reformat the media card, install your ring tones, and try again. If that doesn't help, DK what else to say. Did you try crackberry.com? Sometimes that site has lot more information and you can get more BB users to respond.