I received a brand new 700wx as a warranty return, and it did the same thing right out of the box. The files are all there, but only a few of them would "play". Weird. Hard resets didn't help. That problem along with some other ones (phone not ringing but incoming calls going right to voicemail) caused me to just install Ebag's custom WM5 rom :
http://discussion.treocentral.com/sh...d.php?t=164457
I wasn't convinced the WM6 rom was worth the uncertainty.