The region free utilities in my site are working ONLY for Liteon/Jlms drives, including oem and rebadge (eg: if your Sony is a Liteon it will work, if it's a BTC it will not)
Many other drives can be made region free with either a patched firmware or a (reset) utility, made specially for them.
To find out what are the options for your drive, I suggest you visit the download section of the firmware page. If there is a solution for your drive, you're sure to find it there.
Should there be (yet) no region free fix for your specific drive, you might want to consider a software solution. There are currently a couple of very good region free programs, but alas, not free. It's a shame to have to pay for what I regard as your right, but it's up to you to consider these options. You may try these for free before you make up your mind:
9237