This message may occur when attempting to start "Sight" Survey 2009 with AutoCAD.
This is an AutoCAD issue, not a "Sight" Survey issue, and it is generally caused by the use of registry cleaners, and in some cases by anti-virus software.
To correct this issue you must completely uninstall and then reinstall you AutoCAD application using the uninstall procedures outlined in Autodesk Knowledgebase article TS45252.
Running any registry cleaner software may remove necessary settings. Certain anti-virus programs may also periodically clean your registry keys.