I'd go to the Acer web site and download the network driver. That would seem to be what it's looking for. Have you added any hardware to the original configuration? If so, that's probably the cause of the message.
I reset my laptop to factory settings, it loads up fine and let's me log into my user. When i log in it asks me to "insert the disc that came with your network controller" but I do not have any discs? Can someone help me please