SQL & PL/SQL

When attempting to execute a simple procedure in my own schema, I'm having an error thrown. Can someone tell me why?

Here's the execution code

BEGIN
execute myschema.RUN_NEW_SCRAMBLE;
COMMIT;
END;


This is the error that follows:

ORA-06550: line 2, column 11:
PLS-00302: component 'RUN_NEW_SCRAMBLE' must be declared
ORA-06550: line 2, column 3:
PL/SQL: Statement ignored


when I run the simple command:

exec RUN_NEW_SCRAMBLE;

It works like a charm.

Please advise.