Email problems

[djtenssy]

My server don't send or receive emails, at mail.err (log) only exist this line
Jun 26 14:11:38 ks359210 amavis[29650]: TROUBLE in pre_loop_hook: Can't connect to data source mysql:maia, no database driver specified and DBI_DSN env var not set at /usr/share/perl5/Mail/SpamAssassin/BayesStore/SQL.pm line 1656
but in the mail queue, have a messages (send and receive) with this status:
connect to 127.0.0.1[127.0.0.1]: Connection refused
Please help and sorry for my bad english.
djtenssy.