When attempting to install an update on an Exchange 2010 server (or anything with the management tools on) it is possible to get the error below or one similar to it.
Windows Installer reconfigured the product. Product Name: Microsoft Exchange Server. Product Version: 14.1.218.15. Product Language: 1033. Manufacturer: Microsoft Corporation. Reconfiguration success or error status: 1603.
For me the resolution was to start a command window with elevated permissions (right click, run cmd as administrator) and then run the update from there.
E.G.
Then simply follow the on screen wizard as before and the update should install correctly.