Middle mouse problems in MSCAD 2002

My middle mouse button does not bring up the osnaps how can I fix this?

In the C:\MSX2002\CFG\MICROSURVEY.KEY file or the C:\MSCAD2002\CFG\MICROSURVEY.KEY file, scroll down the file to find the following:

[BUTTON MENU]
RButton=
MButton=

Change it so it says:

[BUTTON MENU]
RButton=
MButton=[CONTEXT MENU]

Then save the file and run MSX or MSCAD. Your mouse should now have the osnaps working again.