ORIGINAL: Caddi06

I have a 1997 Eldorado with the basic factory stereo. I bought an Alpine CD changer and connected it to the wire in the trunk. The problem that I am having is that when I turn the car off and start it back up the CD changer does not work. I have to take the cartridge out of the cd changer and put it back in and then it works. I do get an error message on the radio that says "err". Today when I started the car up the radio was off and would not turn on and there was not even a time dislay on the radio. Then I turned the car off and on and the radio worked but not the CD changer. Does anybody know what the problem is? Is the CD changer bad? Thanks!