Hi Bill,
The MR services can use the Office drivers installed on a server; however, the version of Office that is installed needs to match the architecture of the server (same as MR). When you install MR to a 32-bit server, it installs all needed 32-bit files and drivers. When you install MR to a 64-bit server, it installs all needed 64-bit files and drivers. This is covered in the KB article below:
2544472 Error message when you try to link to a Microsoft Excel Workbook in Microsoft Management Reporter: "The Microsoft Access Driver, Microsoft.ACE.OLEDB is not registered"
mbs.microsoft.com/.../KBDisplay.aspx;en-US;2544472
It is a limitation of Microsoft Office that you cannot have a 32-bit installation of Office on a 64-bit server and install the 64-bit version of the Access Database Engine.
Remember that you only need to install the Access Database Engine on the server running the MR services, not on any of the computers running the MR Report Designer client.
As a side-note, please note that the Microsoft Office Support team has notified MR Support that installing the Access Database Engine using the /passive option is not recommended and may not be supported in a production environment, so this workaround is not included in KB 2544472. If you have questions on this, please feel free to contact the Office team.
One last note is that you do not need a full Office installation on a server to export MR reports to Excel. MR has all of the information needed to do the export built-in. However, you would not be able to OPEN the exported files while logged into the server without Office.
Hope that helps to clear things up!