What you need:
1 blackberry desktop software, innstalled of course
2 Go to RIM country specific website, pick your carrier and download the device specific software. normally there are different versions, one is multilingual(not this one), pick the Aisa or eastAsia version
3 install this, making sure this is the only device software install inn your system.

flash the rom:
1, use your desktop software to back all your data
2, Navigate to C:\Program Files\Common Files\Research In Motion\AppLoader, rename or delete your VENDOR.XML
3, quit blackberry desktop manager
4, now start the command line
4, copy and paste {cd C:\Program Files\Common Files\Research In Motion\AppLoader} and enter
5, copy and paste {Loader.exe /nojvm} and hit enter again
6 follow the instruction on the screen
7 restore your data in blackberry desktop manager

that is it!