Hiya.
I just finished a Google search related to this exact problem and it led me here.
2003 GT, bought used. The radio doesn't recognize that there's a 6-CD player attached, nor does the CD player allow for a CD to be inserted - it's almost as though there's something jammed, although if it's not registering in the system that could very well explain the reason for not accepting a disc.
Anyway, it doesn't seem as though there's a solid consensus regarding a possible cause / solid reason for this to be happening.
I'm gonna keep looking, i guess and check back here as well. It seems Chrysler should have information about this - then again, maybe that's one of the reasons they went bankrupt.