InstaDMG & New Hardware

I'm newish at InstaDMG and I had a quick question. I've created my image on an older Mac Pro using a 10.6 retail DVD and then added the combo updater, etc. The image has worked fine on all my test machines, ones newer than my mac pro even. Today I just imaged a new Mac Mini and the ethernet port is not being recognized. I've checked to see if it was hardware related, but its not. I was always under the assumption that you didn't need to necessarily run InstaDMG on the newest hardware and that since its 10.6.4 that the any machine at this point should work. Should I be using the 10.6.3 disc that came w/ the Mac Mini to make the default image? Or is it simply that I should do the whole instadmg config on the mac mini? Thanks in advance. Allen