FATAL ERROR: database does not exist in the system catalog

I had a database up and running for a couple of weeks on a windows
2000 machine, and had a web application accessing it remotely with no
problems. I had to restart the computer with the postgresql server and
had trouble getting the postmaster started again. I finally got the
postmaster started after deleting the files '/tmp/.s.PGSQL.5432.lock',
'/tmp/.s.PGSQL.5432' and '/usr/local/pgsql/data/postmaster.pid', but
when I try to start the web application that uses the database, I get
the error "FATAL 1: Database "newtestdb" does not exist in the system
catalog". I was also using pgaccess with the postgres user account to
administer the database remotely, but when I try to connect with
pgaccess now I get the error "FATAL 1: User "postgres" does not
exist". The system logfile from today is:

Lock file "/tmp/.s.PGSQL.5432.lock" already exists.
Is another postmaster (pid 2060) using "/tmp/.s.PGSQL.5432"?
/usr/local/pgsql/bin/postmaster: cannot create UNIX stream port
DEBUG:  database system was shut down at 2002-02-19 10:22:58
DEBUG:  checkpoint record is at 0/113640
DEBUG:  redo record is at 0/113640; undo record is at 0/0; shutdown
TRUE
DEBUG:  next transaction id: 89; next oid: 16556
DEBUG:  database system is ready
FATAL 1:  Database "newtestdb" does not exist in the system catalog.
FATAL 1:  Database "firsttestdb" does not exist in the system catalog.
DEBUG:  database system was interrupted at 2002-03-05 10:44:50
DEBUG:  checkpoint record is at 0/113640
DEBUG:  redo record is at 0/113640; undo record is at 0/0; shutdown
TRUE
DEBUG:  next transaction id: 89; next oid: 16556
DEBUG:  database system was not properly shut down; automatic recovery
in
progress
DEBUG:  ReadRecord: record with zero length at 0/113680
DEBUG:  redo is not required
DEBUG:  database system is ready
FATAL 1:  Database "firsttestdb" does not exist in the system catalog.
FATAL 1:  user "postgres" does not exist
FATAL 1:  user "administrator" does not exist
Found a pre-existing shared memory block (ID 128) still in use.
If you're sure there are no old backends still running,
remove the shared memory block with ipcrm(1), or just
delete "/usr/local/pgsql/data/postmaster.pid".
DEBUG:  database system was interrupted at 2002-03-05 10:48:49
DEBUG:  checkpoint record is at 0/113680
DEBUG:  redo record is at 0/113680; undo record is at 0/0; shutdown
TRUE
DEBUG:  next transaction id: 89; next oid: 16556
DEBUG:  database system was not properly shut down; automatic recovery
in
progress
DEBUG:  ReadRecord: record with zero length at 0/1136C0
DEBUG:  redo is not required
DEBUG:  database system is ready
FATAL 1:  Database "newtestdb" does not exist in the system catalog.
FATAL 1:  Database "firsttestdb" does not exist in the system catalog.
FATAL 1:  Database "newtestdb" does not exist in the system catalog.
FATAL 1:  Database "firsttestdb" does not exist in the system catalog.
DEBUG:  statistics collector process (pid 1372) exited with exit code
1
      0 [main] postmaster 1812 sync_with_child: child 1780(0x284) died
before
initialization with status code 0x80
  76636 [main] postmaster 1812 sync_with_child: *** child state
waiting for
longjmp
PGSTAT: fork(2): Resource temporarily unavailable
DEBUG:  server process (pid 1780) exited with exit code 255
DEBUG:  terminating any other active server processes
DEBUG:  all server processes terminated; reinitializing shared memory
and
semaphores
3189629 [main] postmaster 1812 sync_with_child: child 1444(0x358) died
before
initialization with status code 0x80
3206101 [main] postmaster 1812 sync_with_child: *** child state
waiting for
longjmp
DEBUG:  could not launch startup process (fork failure): Resource
temporarily
unavailable
DEBUG:  database system was interrupted at 2002-03-05 11:55:49
DEBUG:  checkpoint record is at 0/1136C0
DEBUG:  redo record is at 0/1136C0; undo record is at 0/0; shutdown
TRUE
DEBUG:  next transaction id: 89; next oid: 16556
DEBUG:  database system was not properly shut down; automatic recovery
in
progress
DEBUG:  ReadRecord: record with zero length at 0/113700
DEBUG:  redo is not required
DEBUG:  database system is ready
FATAL 1:  Database "firsttestdb" does not exist in the system catalog.
FATAL 1:  Database "firsttestdb" does not exist in the system catalog.
FATAL 1:  Database "firsttestdb" does not exist in the system catalog.
DEBUG:  database system was interrupted at 2002-03-05 14:05:20
DEBUG:  checkpoint record is at 0/113700
DEBUG:  redo record is at 0/113700; undo record is at 0/0; shutdown
TRUE
DEBUG:  next transaction id: 89; next oid: 16556
DEBUG:  database system was not properly shut down; automatic recovery
in
progress
DEBUG:  ReadRecord: record with zero length at 0/113740
DEBUG:  redo is not required
DEBUG:  database system is ready
FATAL 1:  Database "firsttestdb" does not exist in the system catalog.
FATAL 1:  Database "newtestdb" does not exist in the system catalog.
FATAL 1:  user "postgres" does not exist
-----
the database "firsttestdb" is the database I had been connecting to
for the last couple of weeks, and the database "newtestdb" is a new
database I created this morning, and connections to both worked for a
while this morning, before the server was restarted.  And the postgres
user is the owner of both databases.
Any idea why the remote systems can't access the database anymore?

Thanks,
Linda