All right, using the latest build of ImgBurn.
On my old nF4 mobo, it worked fine.
Just switched mobos & cpu's. All other hardware, including ram, is the same.
New mobo is an Asus A8R32 MVP Deluxe (a Crossfire X3200 board).
I have the latest BIOS & drivers for everything.
Anyone else using a Crossfire 3200 chipset board having the same problem?