Invalid triggers

hi i tried to compile this invalid trigger but getting the following error. can you please guide me how could i solve this issue. i just did a refresh .

SQL> alter TRIGGER IMMSETUP.WJSBUSTG compile;
 
Warning: Trigger altered with compilation errors.
 
SQL> show err
Errors for TRIGGER IMMSETUP.WJSBUSTG:
 
LINE/COL ERROR
-------- -----------------------------------------------------------------
20/2     PL/SQL: Statement ignored
20/10    PLS-00371: at most one declaration for 'WJSSPPK.GV_STEPSUPDATED'
         is permitted
 
SQL>