While installing the April 2013 CU for SharePoint 2010 Server a colleague came across this error. He checked with me and I remembered that I had come across the same issue while deploying a CU sometime back. The installer does a version check and there is a command line switch to bypass this check which is: PACKAGE.BYPASS.DETECTION.CHECK=1 To get this to work, navigate to the folder where you have the foundation or the server CU and type the name of the CU package, give a space and copy paste the above text and press Enter. This may not be the most elegant way to get rid of this error but at least it does the job because you don't get much information from the error that the installer throws at you!
My experiences with SharePoint and other technologies