Custom ringtone settings not saved iPhone 3G

I lose mine whenever I backup my phone and they arent working at all since moving to the 3GS
iMac Mac OS X (10.5)

I have a similar problem which, as you say, is a bit irksome but not the end of the world. Or at least it wasnt until I realised that some callers ringtones had become silent and the first I new about incoming calls from certain people was an answering service SMS message! If I have to keep calling people back it is going to get expensive. I had some custom made ringtones, using the utility MakeiPhoneRingtone by Rogue Amoeba. I have wiped the ring tones off the phone and am back to the default range of choices to see if that makes a difference. Otherwise, I have no idea what to do. Drew.
G5 dual 2.3 + 4GB RAM Mac OS X (10.5.7) G5, 30" Apple display, HP Z3100 GP + Epson SC3000, G4 PwrBk, iMac + black 5500

I fixed it by deleting all contacts off my phone, then deselecting syncing on itunes. I then added mobileme syncing on the phone and everything is working now.
iPhone 3GS iPhone OS 3.0