Anyone else having this issue?

When playing mp3's - if I leave myself on the MMplayer screen, everything is fine. If I go into another application (or more importantly, no application and lock the keyguard the phone) - as soon as the song currently playing ends, it goes into a reboot. Not an infinite loop.. just a reboot.

When watching movies, not an issue, because of course, you'd be on the mmplayer screen.. but this is annoying if you want to listen to music and keyguard the phone.

RealPlayer on the TREO works fine, so I am using that instead for now...