LMTP with Postfix Problem

Here's a maillog entry that's one of many I receive when I try sending a test message to my system. The recipient is a virtual user in /etc/virtual. The way I'm expecting it to work is that my message from me to this Postfix virtual user will be sent back to me. Every time the message delivery is attempted, Dovecot says the LMTP directory doesn't exist. I thought it was created automatically as messages arrive.

Jun 18 01:48:27 <machine-name> postfix/lmtp[30644]: 4CA5B8CB6: to=, orig_to=<postmaster>, relay=none, delay=0.02, delays=0.02/0/0/0, dsn=4.4.1, status=deferred (connect to <my-FQDN>[private/dovecot-lmtp]: No such file or directory)