Help me debrand my k750i

[SeaMonkey]

I have a K750i CID49, RED havin R1C021_china firmware and when i tried to change the the acoustics file, it didnt respond for the first time after a while it showed "Insert correct sim" whatever sim i inserted. when i connected it in SEtool2 lite it showed Network: Locked. Someone please help me release this lock.

First of all you need MAIN,FS and Custpack for your phone,than you need XS++,
SimLock Patch Generator and SeTool2lite

[sathish14_]

then i have these i dont know how to do it, i tried with a tutorial form this site, but it says embedded bootloader failed to start??? what shall i do now