C333 Network problem

Hello...
I unlocked one C333 with band 850/1900 with Victor soft and passo ..i changed the band to 900/1800 using PST flex option ..the IMEI of the phone is 01016XXXXX ... I can find the 1800 band and it has full signal ..I am not able to make any calls in this ..moreover the phone is not detecting the 900 band... is this due to the IMEI..? Is it possible to change the IMEi with any software..? I am not able to flex the phone in Victor soft with the 900/1800 band activator flex ..i am getting error Unrecognized command in flex.. can someone hlep me with this problem..?


Thanks

Surej