Cant change ring tone.

[chrisb2e9]

Hello,
I have an odd problem with my phone. I can not change the ring tone. Any attempt to select a stock ring tone gives me the message
"the file is not available or is corrupt."
Or something to that effect.
This is only for incoming calls. I can change ring tones just fine for texts, mail, alarms, etc.
The files for some reason are set to hidden and read only. I cant change them either. I have tried many different programs to change the file attribute as its the only thing I can think of that may be causing the problem. the files themselves are fine. I can copy them to my pc and play them without issue.

Any suggestions?

Thanks!