Dell 760 RIS Image

I have recently purchased a number of Dell Optiplex 760s. I am attemtping to image them using my current RIS images. I keep running into the message that ” the operating system image you selected does not contain the necessary driver for your network adapter.” After creating the image upload it and trying to download. I have downloaded the drivers from the Dell site and have followed the MS KB article 315279 “How to add a third-party OEM network adapter to a RIS installation. But am having problem rising