There's no reason to use macro substitution in this case and it'll also fail if there're spaces in the path.

>I know you've gotten answers about a better way to do this but.............
>
>using a macro expansion should work. Unless there's a typo in your message you have one to many &
>

SET DEFAULT TO &cdir

>
>You've actually turned cDir into a comment and have issued

>SET DEFAULT TO