stored procedure skips one delete statement

I have the following stored procedure.  It is compiled and do everything I ask for, except one thing: it does not delete the data in 'SP_FE_PORT' TABLE that I want it to.It drives me nut as I have no idea why it does not.  I can delete the sp_fe_port table if I hardcode the "owner" in the statement.   Could you some look at it and help me to debug the problem.

create or replace

PROCEDURE PURGE_USER 

(

  owner IN VARCHAR2  

) AS 

BEGIN

  delete from SP_FE_PORT where username = owner;

  delete from systemconfig where username = owner;