Don't know mate, I just plugged it in and it told me there was a update. I can assure you I've used no other program to update.
Maybe it depends on where the phone originally come from as to whether the firmware has been released for that region?
That's exactly the case. The particular release of phone you have needs to be in Samsungs list for deployment. There's no tidy way around it really, the best bet is to use Odin to flash the firmware from samfirmware.com.