This is usually caused by incompatibility with the April 1993 driver for the ATI Ultra Pro/Mach 32 video card.

Download the version 2.0 video driver from ATI's web site [link] or from CompuServe (GO ATITECH), or call 416-882-2626.

If you do not succeed, and have version 2.5
Upgrade to 2.5a [Download link].

If you continue to have difficulty
Contact Tech Support [link to contact form]

Technical Support List of Problems