I fixed ERR-01 myself and it was the same situation that you have where the cartridge will not come out. The first thing you need to do is make sure the changer is getting power. There's a fused lead (red wire) that needs to be traced. If the fuse isn't blown and you're able to get current on the other side of the wire with a volt meter then proceed with the following- unscrew the 4 bolts that hold your changer to the rear deck. Disconnect the unit. Remove the changer and place it on a clean towel on your kitchen table or another stable surface. Remove the screws on either side, and carefully remove the top of the case to access the inside of the changer. There are additional screws that hold the suspension mechanism to the bottom case, I removed those as well and took the entire changer mechanism out. This is really easy to do, just make sure you keep track of what came from where. Then, using a Q-Tip and some rubbing alcohol, carefully clean the rubber rollers and any other parts of the mechanism that are visibly gunked up. You can actually turn the bottom gears with your thumb and work the changer mechanism up and down. Reassemble the unit in reverse order. Don't reinsert the cartridge until you you have reconnected the wiring. I can't explain why this worked, but when I put the whole thing back together, the problem went away. When you power up the unit for the first time, you'll hear it go through a check where it runs through all 6 discs and resets at #1. Good luck.

Scott J