"collection does not contain elements at index locations in call to dbms_sql.bind_array"
*Cause: The bound table does not contain elements at both index locations
in call to bind_array of dbms_sql. This is illegal.
Both index locations must contain elements.
In other words tab.exists(index1) and tab.exists(index2) must
both return true.
*Action: Either modify the two indexes or the contents of the table
and try the call again.