If you get this error when synchronizing your windows mobile device to outlook 2007 on your computer,

Run fixmapi.exe in \windows\system32. You might need to make sure activesync and outlook are closed and your device is not connected before running fixmapi.exe.

See this site: http://social.microsoft.com/Forums/en-US/windowsmobile/thread/3b8b1829-8bc2-4e98-9b10-f3b2a5d8ce5c/