Just a quick note to say that once the latest rollup for VMM R2 has been applied, you will need to update the agent on each managed host.  Until the agent has been updated, the host status displayed in the VMM console will be "Needs Attention".   

 To update the VMM agent on multiple hosts, follow these steps:

1. Open the Virtual Machine Manager console.
2. Click Administration , and then click Managed Computers .
3. Select the hosts, and then click Update Agent .
4. Enter your credentials, and then click OK.

978560 Description of the System Center Virtual Machine Manager 2008 R2 hotfix rollup package: February 9, 2010
http://support.microsoft.com/default.aspx?scid=kb;EN-US;978560

This hotfix can be found on Windows Update or downloaded manually.

To manually download the hotfix rollup from the Microsoft Update Catalog, visit the following Microsoft Web site :

Note The Microsoft Update Catalog has different versions of the update package. These different versions have the EVAL , OEM , RETAIL , and WORKGRP labels. Download the appropriate version for your installation.

If the rollup was downloaded from the Microsoft Update Catalog, do the following to install the hotfix rollup package on the Virtual Machine Manager server:

1. Extract the VmmServer64Update-RETAIL.cab to a temporary directory.
2. Open an elevated command prompt, and then run the following command to install the update:
msiexec /update vmmServer64Update-RETAIL.msp BOOTSTRAPPED=1
Note The name of the package varies based on the version that was downloaded.
3. After the hotfix rollup package is installed on the Virtual Machine Manager server, update the VMM agent on the Hyper-V and Virtual Server hosts.