Try following these steps and see what happens.

Make sure there is no DML going on in your DB

run $ORACLE_HOME/rdbms/admin/utlrp.sql as sysdba

Check your results.

Note: It sounds like your a newbie to Oracle. If that is the case, you
may want to look into a third party tool like TOAD. This is a GUI interface
that can aid you with your admin work and help you pin point problems
just by browsing.

Good luck