I've had this recently. I had a perfectly scripted boot disc that wouldn't load the drivers but found that re-downloading the drivers from the vendor and putting them on in place of the other drivers did the trick.

When I downloaded the e1000 driver from the IBM website (I was after the driver for an IBM laptop) the difference in size between the new driver and the old driver was quite considerable.

Try that, otherwise meh, I don't know.