I've installed SQL Server 2005 SP1 RTM on a Windows 2003 R2 machine (machine A), and my local workstation (machine B).
From machine B, I can use SSMS to connect to SQL Server on machine A. This is using either "New Query" or "Object Explorer".
However, on machine A, SSMS can only connect to machines A or B using the "New Query" option. If I try "Object Explorer" for either, I get the error message "Failed to retrieve data for this request... urn could not be resolved at level Configuration."
I'm not sure what died (no pun intended) since the last time this worked. Any thoughts on this

SSMS cannot connect through Object Explorer to anything
Cool Zen
The same was happening to me without making changes on my PC or my SQL server environment.
ERROR window:
Connect to Server
Failed to retrieve data for this request. (Microsoft.SqlServer.SmoEnum)
For help, click: http://go.microsoft.com/fwlink ProdName=Microsoft+SQL+Server&LinkId=20476
urn could not be resolved at level Configuration. (Microsoft.SqlServer.SmoEnum)
For help, click: http://go.microsoft.com/fwlink ProdName=Microsoft+SQL+Server&LinkId=20476"
RESOLUTION was:
1. Open c:\Program Files\Microsoft SQL Server\90\dts\Binn\MsDtsSrvr.ini.xml
2. Modify the ServerName line to read "(local)" or a more specific server name instead of a "."
3. Restart SQL Server service
SAMPLE:
<DtsServiceConfiguration xmlns:xsd="http://www.w3.org/2001/XMLSchemahttp://www.w3.org/2001/XMLSchema">http://www.w3.org/2001/XMLSchema</A< A>>" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
'>http://www.w3.org/2001/XMLSchema-instance">http://www.w3.org/2001/XMLSchema-instance">
; <StopExecutingPackagesOnShutdown>true</StopExecutingPackagesOnShutdown>
<TopLevelFolders>
<Folder xsi:type="SqlServerFolder">
<Name>MSDB</Name>
<ServerName>(local)</ServerName>
</Folder>
<Folder xsi:type="FileSystemFolder">
<Name>File System</Name>
<StorePath>..\Packages</StorePath>
</Folder>
</TopLevelFolders>
</DtsServiceConfiguration>
Good luck!