ORA-06508 when calling SRW package procedures

All,

I was attempting to use the SRW package, installed on the database, to call Oracle Reports from the database server. I found sample code to do this on several websites.

However, when I attempted to test it, I found that, while the package spec is visible, any calls to packaged procedures failed with:

ORA-06508: PL/SQL: could not find program unit being called

Here is my code:

DECLARE

  g_username             VARCHAR2(30) := 'some_user' ;

  g_password             VARCHAR2(50) := 'some-password' ;

  g_tns                  VARCHAR2(100) := 'some_database' ;

  g_filepath             VARCHAR2(200) := 'MONTHEND_DIR' ;

  a_report_name          VARCHAR2(100) := 'COMMSUMM_HTW.rdf' ;

  v_procyrmth            VARCHAR2(20) := '201505' ;