The tool that was supplied with the bios is DOS based (phlash16.exe), that is what I'd use to flash the bios. I could only speculate as to whether WinPhlash will work or not.
1. you are using a loader which messed up your rweverything report. you need a clean report, so remove the loader. 2. i did get the same error msg when trying to mod, most likely it will require a manual mod.