Ringtones don't work

I have different tones on my memory card for txt messages, calendar alerts and etc. I loaded OS 6 and they were all wroking but suddenly the the file for my main ringtone doesn't play. I instead I get a call and some new os6 default ring tone sounds. Help me....I can't figure this one out.

Thanks in advance

I am not sure if the os is your issue but one thing to check - if ringtones are on a sd card, they cannot always be accessed if your usb cord is plugged in with mass storage mode enabled