I'm using the OCT in Office 2007 and have made a .MSP file. When I test it from my PC, it works fine. When I test it from another PC, I get the following error: "The upgrade patch cannot be installed by the windows installer service because the program to be upgraded may be missing, or the upgrade patch may update a different version of the program. Verify that the program to be upgraded exists on your computer and that you have the correct upgrade patch." I'm logged onto both systems and have full permissions to the files. Any suggestions? Thanks, Larry