WINS server is not being queried for entries in LMHOSTS after Service Pack 4.

A. Before Service Pack 4 a resolution request was always passed to a WINS server and only if no entry was found the LMHOSTS file checked.

Under Service Pack 4 any entry in the LMHOSTS file that has the #PRE qualifier (preloaded) will be used and the WINS server not queried. Therefore if you have incorrect entries in your LMHOSTS file it will prevent the WINS server from being queried so you should therefore edit the file %systemroot%\system32\drivers\etc\lmhosts (e.g. d:\winnt\system32\drivers\etc\lmhosts) and remove the offending entries.