This is quite a common problem on the 06-11 Aurions & Camrys, so it doesn't surprise me it has happened to the GSV50 too. What's the exact error message the screen is displaying? It sounds like the CD has jammed inside the tray, likely due to some CD-R's being slightly thicker than regular CD's. The easiest thing to try is to remove your 'RADIO' fuse in your engine bay, or disconnect your battery for half an hour as this will reset your stereo and hopefully eject the CD. Failing that, you'll have to remove the unit and take the metal frame off to try and get at the CD. If it all turns to custard then at least you've still got your USB port ;)