Start DB giving fatal message.(linux)

Because of some OS failure I have to reinstall linux and postgres and now
database start gives me following error message. Any pointers will be
apprciated ...

testuser(at)machine:postgresql-8.2.5$ /usr/local/pgsql/bin/postgres -D
/usr/local/pgsql/data
LOG: database system was shut down at 2007-10-23 16:30:49 PDT
LOG: checkpoint record is at 0/42C408
LOG: redo record is at 0/42C408; undo record is at 0/0; shutdown TRUE
LOG: next transaction ID: 0/593; next OID: 10820
LOG: next MultiXactId: 1; next MultiXactOffset: 0
LOG: database system is ready
FATAL: database "db_test1" does not exist
FATAL: database "db_test1" does not exist
FATAL: database "db_test1" does not exist
FATAL: database "db_test1" does not exist

"db_test1" was one the databases I was using before reinstalling everything.
Note during re-installation, I have formatted the harddrive which has erased
the /usr/local/pgsql/bin/postgres folder ... but there were some stuff that
persisted as it was on NFS (this includes the installer for postgres) ...

BTW, where does postgres saves all db related information which is used at
db start time. Is there a utility to edit this information??

Thanks .. Farhan