Oh...where are you flashing from? Windows?
Yeah, that's not the best idea and most companies don't have a Windows flash utility.
If you've got a Win98 startup disk, that'll do.
On a 2nd floppy copy all the files that are in the .zip file (I presume that's what you've d/l'd). Make sure to back up the current BIOS before flashing in case the new one makes things go down the crapper.
Backing up...with the Win98 floppy boot off of it and hit [Shift]+F5 (I think) when you get the selection screen.
Follow the flashing instructions (printing them out before going to flash wouldn't hurt if you have questions) and make sure to back up the current BIOS in case things go bad.
Oh, and when I said about the BIOS being write protected...I meant the BIOS chip on the motherboard, not the BIOS you downloaded.