Execute SQL Task - SSIS

A stored function is created in MySQL Server running on Linux with following info:
mysql > delimiter $$
mysql > CREATE FUNCTION GetMaxKeyForSampleTable()
-> RETURNS DOUBLE READS SQL DATA
-> BEGIN
-> RETURN (SELECT MAX(MJD) FROM tblSampleTable);
-> END;
Query OK, 0 rows affected (0.02 sec)
mysql > delimiter ;

***The above function is successfully stored in the database.

"Execute SQL Task" add-in module has following info:

Name: Execute SQL Task
Description: Execute Task
TimeOut: 0
CodePage: 1252
ResultSet: Single row
Connection Type: ADO.NET
Connection: .MySQLServerLinux
SQLSourceType: Direct Input
SQL Statement: SELECT GetMaxKeyForSampleTable() AS MaxKey
IsQueryStoredProcedure: True
ByPassPrepare: False

Result Set:
Result Name Variable Name
MaxKey User:_dMaxKey

The following steps are taken:
1. Clicked "Parse Query" push button which results a pop-up dialog box -
"The query parsed correctly".
2. Clicked "OK" button.
3. Right clicked "Execute SQL Task" add-in module.
4. Selected "Execute Task".

"Execute SQL Task" changed its color from white to yellow to red
which means excution failed.

Please help me to figure out what should be done to make the excution successful.
Thank you very much in advance.

Paul Cho