Hye
I had a similar problem and I solved it by :
* deleting and re-creating the user with passwd
* Verify in pg_hba.conf the access and users (It is at this level I had
problem from fields -be carefull with the editor- and the "identuser" /
try to put trust in a first time)
* giving rights to this user to my db
* using psql -U username -d dbname
I hope it helps
mp torre