I have been using Firefox for quite some time now on my openSuSE 10.2 box with proxy server set manually. I updated my system with some softwares other than Firefox and all of a sudden since yesterday the firefox is giving problems related to proxy server. This is the message:

------------------------------------
Server not found


Firefox can't find the server at www.google.com.

* Check the address for typing errors such as
ww.example.com instead of
www.example.com

* If you are unable to load any pages, check your computer's network
connection.

* If your computer or network is protected by a firewall or proxy, make sure
that Firefox is permitted to access the Web.

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I use the same proxy for Konqueror and Opera, and they work fine.

I even saw that SUSE firewall is also disabled.
Are there any changes to be made in the firefox to get it to original shape?

Which means, that you have no access to the internet.

You might have a problem with your network card.

Is it a wireless or wired?

Doesn't sound like a network card problem.
I've had the same with FF & proxy, so I use Konqueror if I want or need a proxy.... either with JAP or Tor(k).
FF 2.0.0.4 seems to work with Tor.