I've been looking since this morning and found nothing on modmyi.com to help me, even posted twice and no help by anyone.

Luckily I found a solution by just searching around the internet and dont ask me how but I stumbled onto this site, tried it and AMEN, it worked!

How To Fix “Different SIM Detected” After iPhone Jailbreak | The iPhone and iPad Blog by Simon

Follow the tutorial

ADMINS try putting this as a sticky or at least make your own version of it, I'm sure heaps of people will be happy and help them out a lot!

Say thanks =} *feels great helping out the iCommunity for once*