NIC is Network Interface Card, and is your network card, evidenced on your computer as a port that looks like a telephone jack except a bit squarer. Basically it sounds like the installer cannot see it. Now this could be due to the fact that the operating system itself cannot see it because the drivers for it are not installed.
To check this go into 'Device Manager' on your computer; this can be found under the 'System' icon within the Control Panel. If you cannot find it, then just open up your OS help file (assuming you're on windows then hitting F1 when you're on the desktop will bring it up) and search on 'Device Manager' and you should get a link directly to it. When it opens, look under 'Network Adapters' and see if anything is listed. If there isn't, or if there is but it has a yellow question mark by it, then the drivers for your NIC are not installed correctly. You will need to find and install them. The PC manufacturer's website is usually a good start, as most provide drivers for most system components for download. If in doubt call whoever supplied your PC.
Else, you may need to contact your broadband provider and see if they know of any incompatibility issues, although that is very unlikely.