Try this:
In Windows Control Panel, open the System item to open the the System Properties dialog box.
On the Advanced tab, choose Environment Variables.
In the Environment Variables dialog box, under System variables, choose New to open the New System Variable dialog box.
In the Variable Name box, enter ACADCFG.
In the Variable Value box, enter the location of the configuration (CFG) file.
Choose OK in each dialog box to close all open dialog boxes.
Good Luck!
Cassy