IPhone :: Suddenly - No Incoming SMS Sound Notification!

I did SSH my iphone using DISKAID, and in DISKAID there's this random glitch where sometimes when you're renaming a file it will name the whole folder the new name, and it happened to me with the MobileSMS.app folder, but i changed it back and didn't notice any problem. about an hour later i get a text (sound works), and while typing my reply the SMS app froze (if it's any clue it was during the magnifying glass thingy was on). I went in and out of the app using home button (multitasking enabled) but it wouldn't unfreeze so i rebooted the phone and it came back normal. but since then- no incoming SMS sound!

What's even weirder than that is the fact that even if i'm going to SETTINGS SOUNDSNEW TEXT MESSAGE and tap the different ringtones I don't get any sound!

Oh - another clue:
During my browsing through the phone's file system I did find another "ringtones" folder somewhere and deleted them all except for two - but as far as I know the call ringtones and the SMS ringtones are never in the same folder.. still, could I have deleted the SMS ringtone files? that would make pefect sense but.. is it even possible? or could it be something I accidently changed in the MobileSMS.app folder?