EBS Servers: Microsoft .NET Framework 3.5 SP1 fails to install – KB951847

You may see installation failures of Microsoft .NET Framework 3.5 Service Pack 1 (KB951847) on the 3 EBS Standard Edition Servers. Clients and other servers are not affected. The behavior is that the update will fail to install and continually be offered each time you check for new updates. To correct this, run the following steps on all 3 EBS Servers.

More info: EBS blog