What does DNS lookup failed mean?

It actually means Google Chrome could not connect to a DNS server to find the I.P address of www.google.com. Basically it means you don't have internet connection. If you are getting internet on your iPod then it could be some wrong networking setting on your computer. Probably you have set up to use a static I.P address. You can change this by changing your TCP/IP settings. In your TCP/IP settings page, instead of choosing use the following I.P address choose Assign a I.P address automatically.