anything in the sounds folder cannot be used as a ringtone.
the best way to get them on the phone is with QPST (google and download)
once in QPST and you can see the file system.
delete my_ringtone.dat and my_ringtonessize.dat
then put add ringtones to the following folder.
brew/16452/lk/mr
then reboot phone.
if you have any problems just ask in here.