6 cd changer problem?

I have a 94 lexus es 300 with a 6 cd changer in the trunk. When I put the cd's in and press cd on the radio in the car it says "load" and after a while it will say "error". Any ideas what wrong with it? My friend says the cd changer may need to be cleaned. NOTE: the cd's where clean. How do I fix this problem b/c the antena is busted and there isn't a palce to put cd's in the front, only in the trunk