ethernet error: cannot find Mac address

I have a 2009(I think the late summer one) running OSX 10.7.5. My wifi card or some type of software issue has been causing my wifi to be really spotty, so I purchased an ethernet cable and plugged it in. The network settings showed it to be working fine. There was the green dot and it said it was connected via ethernet. When I opened up my browser and a white screen with a message saying "error: cannot find MAC adresss. Cannot proceed" shows up. This happens in both of the browsers that I use. Can anybody help me with this issue. Thanks in advanced. BTW, I'm connected to the internet via WIFI right now, it's working fine right now, but it's very inconsistent.