I know this is an old post but in my search of trying to find out why I had that exact error of:
Apr 14 18:03:08 flamingweasel postfix/smtp: fatal: specify a password table via the `smtp_sasl_password_maps' configuration parameter
Is due to a typo in your configuration that goes undetected (very similar to writing C or C++ code and doing variable assignment with '=' where you meant to do conditional testing with '=='). The line you have is:
smtp_sasl_auth_enable = yes
Where you want it to be:
smtpd_sasl_auth_enable = yes
The omission of the letter 'd' there has made my life very difficult, but that's the answer to the fatal error in the log file.