I know you are new here, but it would help us and you if you could be more specific in the future. Save us guessing and the possibility of a wrong guess. It wastes your time too trying suggestions from us that are based on a guess.
Something like :
I installed Ubuntu 10.10 (server edition ? desktop edition ? )on my desktop, laptop, netbook (what ?) I try to connect to the internet ( wireless, wired ?? ) using FireFox (?) and I can't get on. The error message I get is : ???
Above is just a friendly suggestion
Anyhow - reading between the lines, try to hook whatever you are using with a wired connection and boot with it. If you are using the GUI or windowed interface you should see on the top window bar an icon saying something like "additional drivers are available". In that dialog box you should see the firmware for your wireless adapter.
The reason for this is Ubuntu will install most common things you need on the install cd, and expect to be connected to the internet for the rest. Of course, it can't update the rest ( proprietary wireless, video etc drivers ) if it can't get on. Sort of a Catch 22.
Good luck and let us know how you are doing.
Edit : I'll second TobiSGD's remark : get a supported version of Ubuntu.