You don't give any information what you are actually doing in your code, so
the only help I could give is a pointer to the error message and its
explanation:

$ db2 "? sql0519"


SQL0519N The PREPARE statement identifies the SELECT or VALUES
statement of the open cursor "<name>".

Explanation:

The application program attempted to prepare the SELECT or VALUES
statement for the specified cursor when that cursor is already
open.

The statement cannot be prepared. The cursor was not
affected.

User Response:

Correct the application program so it does not attempt to prepare
the SELECT or VALUES statement for a cursor that is open.

sqlcode : -519

sqlstate : 24506