Best initial guess is that the drivers for your wifi adapter are not in the disto. This usually occurs when a manufacturer is snotty about allowing the use of their drivers. I know that there's a lot of problem on Macbooks because of this, but I know for example, that there are drivers that can be gotten and loaded for this situation. There may be a solution like this for you. Do some searching around about wifi drivers for linux or your specific distro and you'll probably find some intormation.
keith