First question...were you using those sticker labels? If so, don't use them again. Besides creating an unbalanced rotation (which makes reading the data tough), they tend to snag on things.

A method that works for me a lot is to simply hit the reset button...even when they're jammed, it usually takes care of ejecting the disc, just remember that you'll lose all your presets when you do this.

As for the changer compatibility...not sure, but I don't think so. I know that Sony owns Aiwa, but they're not the same stuff.