why can't I do this?

[Adam McKenna]

in .qmail-default:

/home/user/$EXT/Maildir/

i.e., if I send mail to [EMAIL PROTECTED], mail should go to
/home/adam/foo/Maildir/

qmail defers the message: 
@4000000038fce0c3041b6634 delivery 38: deferral: Unable_to_chdir_to_maildir._(#4.2.1)/