I encountered this error on my Mac Mini 2,1 with replaced Mac Pro 802.11n wi-fi card, back when the App Store first came out, 10.6.6. I followed this fix of trashing the networkinterfaces.plist and re-creating it from scratch: https://discussions.apple.com/thread/2731156?start=0&tstart=0 That fix worked on 10.6.6, was unnecessary on 10.6.7, as I didn't encounter the problem then, and is now happening again since upgrading to 10.6.8. Unfortunately, the fix doesn't appear to be working this time. The one thing I noticed is that, after deleting the networkinterfaces.plist and rebooting, when I re-added my network adapter back in, it automatically remembered my preferred wi-fi network and password. For some reason, I'm thinking it did not remember those things when I had to perform this fix the first time many months ago. Anyone else having this problem?