You can eliminate lots of questions about your computing environment by doing providing more information.
Click Start, Run and in the box enter:
Click OK, and when the System Summary info appears, click Edit, Select All, Copy and then paste back here.
There will be some personal information (like System Name and User Name), and whatever appears to be private
to you, just delete from the pasted information.
Here is a MS article I found with a Google search about your MMC issue:http://support.microsoft.com/kb/914231
What exaclty does your message say when your update fails? Maybe something to do with 0x8007007E?
There are several reasons why the update might fail and different solutions, so more details are better.