He wrote, he gets the message SIM Card Error WITHOUT a SIM is inserted.....
Cleaning the SIM Card and ensuring the connection doesent match......
Open connections cant couse an error if no SIM is inserted...
Sonds like damaged HW like S-Gold, RAM, or some wrong Signal-Levels on CC I/O(ChipCard Input/Output) or CC RST (ChipCardReSeT).
1st : Look in Shematics and try to exchange the ESD-Protection Diode (V1605) , PullUp Resistor R1614 (4,7K VDD_SIM -> SIM_I/O) and C1606 (18pF) this can couse such an error, but not the only possibility. (This are from M65 Diagramm - but values of those parts the same, maybe they have other names)..
2.nd : if this does not function, try to rehot S-Gold, RAM and Flash.
3.rd : If not works, exchange SRAM and/or S-GOLD or both...
greets from cloudy Duisburg