must delete SystemConfiguration folder to connect to internet w/AP Extreme?

Ok this started happening about 7 months ago and it happens now about every two weeks. My internet connection will drop out for seemingly no reason (although the connection to the AirPort Extreme apparently remains intact) and there is no way to get the internet back. Restarting computer and/or airport extreme and/or modem doesn't work.

So I took it to the Mac Genius and he said to delete the following file then restart the computer: macintosh hd / library / preferences / SystemConfiguration

So I do that about every two weeks when the internet drops out, and it works fine.

But it's rather annoying.

This must be some kind of ongoing problem that Apple knows about, since the Mac Genius knew about it, and they kind of seem to be the last to know.

Thanks in advance for any thoughts.

(I don't think it's an issue, but I do have a Western Digital FAT-formatted hard disk connected to the Airport Extreme which I sometimes use for my iTunes library. But there doesn't seem to be any correlation between the network hard disk use and the problem described above.)