Hi Greg.

It's always a possibility that it did not install correctly and so the location of the files is wrong. :-/

Download this tool from Flight1 - FSX/FS9 Registry Repair Tool - and run it.
After you have done that, reinstall the 767-300 (using "Run as administrator").

Another thing. Are you running FSX "as an administrator"? It's worth a try. Right click on the FSX shortcut and select "Run as administrator".

Mark