Motorola SLVR copying mp3's Itunes

I've had my phone for quite some time now and never really used it for a mp3 player till recently. The other day I copied over some mp3's with Itunes with no problem at all. But now when I plug the SLVR up and try to drag mp3's over to the phone in Itunes it's has the crossed out symbol like you can't do that?? Anyone have any solutions? I'ved tried reinstalling Itunes and looked at all the settings in Itunes but I can't find any answers.

Just a quick FYI, I did try formatting the little Scandisk that's in the phone. But, I'm still unsuccesful with getting MP3's on the phone. =(