O.S.11.2 "Unknown scan mode" message at boot.

I did a new/clean install of O.S.11.2/KDE 4 onto my hardware, using an old Matrox G450 PCI display card. The card is overwhelmed trying to write to my IIyama display (1600 x 1200). so I reverted to the motherboard graphics chip - Intel 865G and to a 1280 x 1024 display. But on every boot I get the message that scan mode 31E is unknown and invites me to pick another one. I always pick 31B (which is VGA 1280 x 1024) - but the same message appears on the next boot.

This happens even if I use the System Utililites appln. to set the display resolution and scanning frequency.

What am I doing wrong>