WSUS Clients are not getting Updates

I'm seeing some indications that the SP1 installer, in some instances, removes the /selfupdate virtual directory from the Default Web Site.
So u have to create a virtual directory named 'selfupdate' with anonymous access enabled, and link it to the pathname at "C:\Program Files\Update Services\Selfupdate "
Check the folder permissions on the SelfUpdate directory, located at "C:\Program Files\Update Service\SelfUpdate", Make sure the IUSR_ComputerName has Read&Execute, Read, List Folders permission on the folder. (In some cases the IUSR_ComputerName permission is missing.)

Transfer WSUS updates to another server

Step 1: Install WSUS on the new Server
Step 2: Match Advanced Options on the old WSUS Server & the new WSUS Server

1. In the WSUS console of the old WSUS server, click the Options tab, and
then click Advanced in the Update Files and Languages section.
2. In the
Advanced Synchronization Settings dialog box, check the status of the settings
for Download express installation files and Languages options.
3. In the WSUS
console of the new server, click the Options tab, and then click Advanced in the
Update Files and Languages section.
4. In the Advanced Synchronization
Settings dialog box, make sure the settings for Download express installation
files and Languages options match the selections on the old server.

Step 3: Copy Updates from File System of the old WSUS Server to the new WSUS server

Backup WSUS updates at WSUSInstallationDrive:\WSUS\WSUSContent\ &
restore it to the new server WSUSInstallationDrive:\WSUS\WSUSContent\. ( U can
use ntbackup to do so)

Step 4: Copy Metadata from Database on the old WSUS Server to the new WSUS Server.

1. At the command prompt on the old Microsoft Windows Server Update Services
Server server, navigate to the folder that contains WSUSutil.exe.
2. Type the following:
wsusutil.exe export packagename logfile (wsusutil.exe export export.cab export.log)
3. Move the export package you just created to the new Microsoft Windows Server Update Services Server.
To import metadata to the database of the new Microsoft Windows Server Update Services Server.
Note:It can take from 3 to 4 hours for the database to validate
content that has just been imported. Please be patient.
1. At the command prompt on the new WSUS server, navigate to the directory that contains WSUSutil.exe.
2. Type the following:wsusutil.exe import packagename logfile (wsusutil.exe import export.cab import.log)