Follow the steps outlined for Excel 2003/2007 and Windows 2008 as noted in the "Known Issues" section of the FDM ReadMe.pdf
When using Windows 2008 server x64, create the following directory on the FDM Application Server(s) to enable Excel importing and exporting:
When using Windows 2008 server x86, create the following directory on the FDM Application Server(s) to enable Excel importing and exporting:
Lastly, bring up the Task Manager on all FDM Application Servers and end any hung Excel.exe processes.
I had this issue as well with our DEV environment, but not our PROD. I compared the two server directories for this path and found that it was present in PROD, but not in DEV. I created the directory as suggested on our FDM DEV servers, then killed off the EXCEL.exe processes that were hanging. I can now perfrom the mapping exports with excel. Worked perfectly!