Have you tried the screen adjustment by adjusting the screws in the battery compartment? I have heard that if you unscrew the 2 screws too much it causes the Sim error. The 2 I am talking about are the one on the right with the red sticker and the one directly opposite on the left side. If you take a hex head and tighten them a tiny little bit it should fix your Sim error and might tweak your touch a bit.