MiniSetup Cannot Find a File

I have a sysprepped image created on an Optiplex 755 with fully enumerated drivers in the sysprep inf file.

We received new Optiplex 760s and a new image was created. The appropriate drivers were loaded and the oempnpdriverspath portion of the sysprep inf was updated to reflect this.

When the new image is deployed to an Optiplex 755, Minisetup fails with the error message
"The file 'Prounstl.exe' on Intel(R) Pro/1000 Driver Disk is needed."

Likewise, if an image created on a 755 is deployed to a 760, Minisetup fails with:
"The file 'e1k5132.sys' on Intel(R) Pro/1000 Driver Disk is needed."

The Optiplex 755 and 760 have different network cards, but the image contains drivers for both.