This messagge because the phone has an USIM-LOCK (is not hardware lock but a network H3G lock, not removable with any tools). If you unlock the phone with Patch generator you can use other sim from other providers.
You can't extract the firmware on Db2020. You must to have MAIN + FS + CP files to debrand and then unlock it.I have another unlocked k800i that came direct from the manufacturers, can i use this to gain the files???
Im in the Uk and the handset is CID 49 not 51.