pg_restore authentication failure

Hi List

I done a pg_dumpall and now would like to load the data back into my new
database. I am doing:

psql -e nachahmer < /home/ywesee/pgsql/pgsqldump.sql

And get:
ERROR: Language plpgsql already exists
\connect: FATAL 1: IDENT authentication failed for user "nachahmer"

at the end of the message. Do you have any idea what could be wrong?

My pg_hba.conf is:
local all trust
host all 127.0.0.1 255.255.255.255 trust

Thanks for your help.
Zeno