a little info i found on
http://support.microsoft.com/default.aspx?scid=kb;EN-
US;326693

Method 2
View the Windows Update.log file to look for error codes.
When an error occurs, it is typically logged in
hexadecimal format. If the hexadecimal error code begins
with the "0x8019" prefix, you can convert the last three
digits of the error code to decimal to obtain the HTTP
status code that was returned to the client during the
detection cycle.

For example, you can convert hexadecimal error code
0x80190194 to HTTP status code 404 ("File Not Found") by
converting the last three digits of the error code (in
this example, 194), to decimal to obtain HTTP status code
404.

Error code 0x80072EE7 is another common error code that is
logged in the Windows Update.log file. This error code
indicates a name resolution problem; the client cannot
locate the Software Update Services server. In this
situation, you can work around the error by using either
the IP address or the full DNS name of your Software
Update Services server when you configure your policy
settings