When exporting Contacts to a PST file I get the error message "The messaging interface has returned an unknown error. If the problem persists, restart Outlook".
I followed the directions in a similar post that suggested to use MS Fix It to unload Office 2007 and then reinstall a clean copy. It also suggested trying to load the Importers & Exporters for Outlook which I tried to do also, but I'm not sure that they loaded properly. When I went back into the install disk to see if the Importers & Exporters installed properly, the option to install Importers & Exporters is not highlighted as if it has already been loaded onto my computer.