I had a more qmail aware friend look at my configuration, and while I have no idea how it happened, the problematic domain got added to the /var/qmail/control/locals file. Once I removed the domain from that file and restarted qmail, everything now works perfectly.
Does anyone have any ideas on how that got added to the locals file? I am running Webmin/Virtualmin on this server (and other servers), but I've never had this happen before. thanks for all your suggestions. -Hank
