SQL & PL/SQL

I usually connect to sqlplus on a personal oracle database (or two other databases) with the usual string
user: myname
password: mypass
host id: Geology1

if I try to log on to sqlldr with
sqlldr userid=myname/mypass parfile=myparfile.par
I get an ORA-01017 error - invalid username/password; logon denied.

the same happens if I give it myname/mypass@geology1 or if I try to use system to log on

Any suggestions please?

Thanks Glenn