I followed the instructions to use the /passive switch here, after downloading the 64 bit Access database engine. I'm running Office 32-bit, SSAS Tabular Model in SQL Server 2012. When I downloaded and ran the 64-bit Access database engine it came up with a message saying that I couldn't install this without first uninstalling Office 2010, but the /passive switch seems to have solved this (I can now import Excel workbooks and Access tables in a tabular model).