You might encounter the error below when installing PowerPivot add-in for Excel.
In more than 50% of the scenarios that I have encountered, the issue was that the user was not installing the right add-in. For example, you would get the error if you are installing a 64-bit version of PowerPivot on a 64-bit machine that has 32-bit version of Excel 2010. When installing PowerPivot add-in for Excel, you don’t look at whether you have a 32-bit machine or a 64-bit machine, instead, you should look at whether you have 32-bit Excel or 64-bit Excel. In other words, if you are using the 32-bit version of Excel 2010, you must use the 32-
bit version of
PowerPivot and if you are
using the 64-bit version of Excel 2010, you must use the 64- bit version of
In case the above solution doesn’t work, you can try the suggested resolution in the following KB article - http://support.microsoft.com/kb/982765 or the following on MSDN forums http://social.msdn.microsoft.com/Forums/en-US/sqlkjpowerpivotforexcel/thread/2ca95318-51de-4603-9d57-8645c164b307/
Hope this is helpful!