I have a similar problem, but found the following workaround. (dual-booting Windows 98 and Knoppix 3.3. Sorry, folks, but we have only one computer, and my daughter, who is resistant to change, won't use Linux!)

When the computer is turned on, it loads BIOS, etc, and stops on the following prompt:

GRUB>

To boot Windows 98 (found this somewhere on the net) I type:

rootnoverify (hd0,0)

then I press "enter," then I type:

makeactive

and again press "enter," then type:

chainloader +1

and again press "enter," then type:

boot


Then Windows 98 boots up.

To boot into Knoppix, I simply put in the floppy rescue disk that was created during the hard drive installation process, and it automatically boots the Knoppix on my hard drive.

I'm sure there's a way to make all this happen without all the typing, but I haven't got there yet!