Based on what you've written so far your door optics are still suspect. Also make sure that the bill validator stacker (cash can) door is completely closed. The C_01 error in the top box will resolve itself once you get the 3100 error cleared.
When you swapped the door optics out with known good ones, were you careful to connect them correctly? IGT stupidly made the connection for the emitter and receiver the same size plug, so it's possible to inadvertently connect the wrong component to the wrong wires.
The emitter has red and black wiring, and should be installed on the portion of the door that swings open. The receiver has a slightly more domed appearance to the part, and has red and white wires, and gets installed on the inside of the cabinet and does not move when the door is opened.