ZEN 7 imaging partition and Dell GX270

I am using ZfD 7 and have created imaging partitions on my lab stations.
The systems are Dell GX270's and when the imaging partition starts, I get
the following error: You passed an undefined mode number
Press <RETURN> to see video modes, available ...

This only shows up on the GX270. I don't have this happening on any other
model I have. Does anyone know how to get around this?

Darrell