5210 Help Please

[striker1]

Hi Guys

Firstly i would to say i am new here and secondly thanks to you guys i have reflashed and unlocked 2 x 8210's.... but i have this 5210 that just wont unlock ? well nokiatool 18 says the phone is unlocked but when i insert a sim i get full signal, when i dial a number i get the no signal beeps ??

Also i have seen posts about changeing th Imei number ?? may i ask what do u change it too?? any of the digits or do i need a full number ??

Sorry to go on

Any help would be greatly recieved

thanks in advance