I currently have A Sony

Question

I currently have A Sony Ericsson K800i and want to switch my SIM into a Nokia N96 which used to be my sons.once the sim is in place it says SIM failed and does not register.The SIM is on Orange network and thay have suggested a software problem as my son used to use A Jabra bluetooth headset with it.According to Nokia's website the software is up to date.Any suggestions please??