So I decided to put a stock headunit which is from a 94 GMC Jimmy (Our family beater) and well I sold my old Panasonic headunit and installed this one since I hardly even bring the stereo with me and I wanted to help out my uncle since he broke his DVD player headunit.

Here is the thing, When ever you put in copies or burnted cds it never reads them, gives ERR and ejects them. Anyone else know how to get around this? or what special burning methods I might have to do to get it working?

If it can't read em... it can't read em. A lot of early, cheap radios can't play CD-R's unfortunately. They just aren't programmed for em. You're gonna have to save up and get something that can read em. While you're at it try and get one that supports Super Audio CD's too. Better sound ftw!