Oracle Database Discussions

Hello, I searched for this problem but not having much luck. I have Oracle 9iR2 running on Solaris 9 workstation. I can log on giving sys/passwd as sysdba and log on using any other user accounts. What I can't do is get into sqlplus using /nolog. I am setting up a dataguard physical clone. The clone is another 9iR2 workstation and i just installed the RDBMS software without creating a database. I can go into this database with sqlplus /nolog. I cannot do this on my intended primary database. I remember being able to get into the database when i first set it up using sqlplus /nolog but have since changed the unix account password and i believe this caused it but when i change the password back to the same one when I created the database, it still does not work. The error I get is SP2-0640: Not connected. Is there a log I can look up that will give me more information? thanks,

Jim