I suspect you enabled the dovecot LDA through master.cf (?)
The option
mailbox_command in main.cf should work better:
Code:
mailbox_command = /usr/local/libexec/dovecot/deliver
Not sure if this is the reason thing don't work, but you could try it...
Also note that you should separate tags with commas (,) not with spaces (You created one very long tag instead of several separate) ...