posgres can't login?

2006-11-11 08:27:10 EST 6158 [unknown] LOG:  connection received: host=[local]
2006-11-11 08:27:10 EST 6158 postgres FATAL:  password authentication failed for
user "postgres"
2006-11-11 08:27:11 EST 6161 [unknown] LOG:  connection received: host=[local]
2006-11-11 08:27:11 EST 6161 postgres FATAL:  password authentication failed for
user "postgres"
2006-11-11 08:27:11 EST 6164 [unknown] LOG:  connection received: host=[local]
2006-11-11 08:27:11 EST 6164 postgres FATAL:  password authentication failed for
user "postgres"
2006-11-11 08:27:12 EST 6167 [unknown] LOG:  connection received: host=[local]
2006-11-11 08:27:12 EST 6167 postgres FATAL:  password authentication failed for
user "postgres"
2006-11-11 08:27:12 EST 6168 [unknown] LOG:  connection received: host=[local]


I get this at every startup but I can't find anything that does not work.

I did change the postgresql.conf file for authentication of local postgres
access from 'sameuser ident' to 'md5'.  Is this something I can effectively
ignore? (If so, why FATAL?) or is there something I can do to fix it (without
going to sameuser ident)?