mmm i think you're right and it's not the same installation as i have not defined the PGDATA environment variable yet, so i don't know what he started at boot time...(i run the db with the -D option right now)
another thing i forgot to say is that the first time i put the data folder in my user home(/home/alex/.postgres/data) instead of /usr/local/pgsql/data/ ...but user postgres should be a SU so it shouldn't make any difference, or am i wrong?
then i changed the folder to /usr/local/pgsql/data/ but pgadmin refused still to connect. Only after i slaughtered /etc/init.d/postgresql-8.1 i was able to connect with pgadmin...
Sounds like you are in a proper mess of defaults, command line options and envvars!! I'd hunt down all clusters (maybe, find / -name postgresql.conf), figure out which one you want to start, and then make sure that you either start it with the -D option, or by explicitly setting $PGDATA first. Don't rely on su to preserve the environment or anything like that as you're bound to run into trouble as soon as you type 'su - postgres' instead of 'su postgres' without thinking.
Regards, Dave