It's resolving IP to name so DNS seems fine.
Does it give any output when you ping it or does it just hang?
Does your company use a proxy server? Maybe ask your admin guy how local computers actually connect through the internet, whether they have direct access or not.
Could be something to do aswell with joining the domain - windows one I assume. You probably need to configure Samba to actually join the domain, all the other machines have joined the domain and are authenticated by it yah?, but seeing as I've never used it like that perhaps someone could clear up the in's and out's of joining a Linux machine to a presumably w2k server domain (if it is) All if's and but's
It could though be as simple though as having to specify a proxy in your browser.