trouble connecting windows Vista to a windows sbs 2003 domain

having issues connecting a Vista comp to my sbs 2003 domain. Kicks back a bad DNS setting. It pops up the authentication promt and i can get too the server by browsing too it. am I missing something? my DNS setting are set to the domain server I can browse internet and when i do a nslookup it show’s my sbs server.
any help out there?