There appears to have been a problem installing the Windows Agent Update - I suggest that you run the CheckSUR tool and see if it finds anything...
Please run the CheckSUR tool from http://support.microsoft.com/kb/947821
(you'll need to look in the details for Method 2)
Then zip the CheckSUR.log and upload it to your public SkyDrive so I can take a look - post a link in your reply.
The tool can take anywhere from 5 mins to a couple of hours to run (or 'Install') depending on how much it has to do, and may exit silently - it may appear to freeze for most of that time, but be patient.