Oracle Message SQL-02124 - NULL value returned by EXEC TOOLS statement

ERRORNULL value returned by EXEC TOOLS statement
CAUSEA NULL value was returned by EXEC TOOLS for a host variable that lacks an indicator variable. This error is returned only when MODE=ANSI. When MODE=ORACLE, although the value of the host variable is indeterminate, no error is generated.
ACTIONAssociate an indicator variable with each host variable to which nulls might be returned.