The System Variable Editor is a tool included in the AutoCAD Express Tools which are an option when Installing AutoCAD 2006.  Lee Ambrosius has graciously updated the data file for the AutoCAD 2006 system variables because we had for some reason missed updating it when we released AutoCAD 2006. I have wrote previously on the System Variable Editor and its nice features. Link

Download sysvdlg.dat

Place the sysvdlg.dat file in the  \Express directory such as the location for my install of AutoCAD 2006: C:\Program Files\AutoCAD 2006\Express\

   
Express menu: Tools  System Variable Editor
Command line: SYSVDLG

Thank you Lee!