Hmm.. you changed your post considerably after the first responses..
My respons for newaliases was about the 95% error messages in your original post. Regarding the location of aliases; if it's in /etc/mail on your system, change postfix; postfix expects aliases in /etc on your system (that's what is says).
Regarding not being able to log in:
Apr 20 03:48:57 ubuntu2 imapd: LOGIN FAILED, firstname.lastname@example.org, ip=[::ffff:127.0.0.1]
Don't use your emailaddress, but your username to login. That can be the same (andrew), but also a different name. (normally, use a "to=" username that you stuffed from the logfile).