sp_getapplock script not working in SSIS(data tools 2012)

Hi,

I have a SSIS package created in 2012 data tools. I have added sql tasks to create and release the locks.

Create the lock script in sql task1:

DECLARE @ProcResult int = 0;

-- Get an exclusive application lock on the package execution resource, to prevent other executions of the same package from doing the same
EXEC @ProcResult = sp_getapplock @Resource ='a',
                                 @LockMode = 'Exclusive',
                                 @LockOwner = 'Session',
                                 @LockTimeout = 0; -- Do not wait for the lock
IF @ProcResult < 0
    RAISERROR('Failed to acquire application lock on %s. sp_getapplock returned %d', 16, 1, @PackageResourceName, @ProcResult);

Release the lock in sql task 2:

DECLARE @ProcResult int = 0;

-- Release a previously acquired exclusive application lock on the package execution resource
EXEC @ProcResult = sp_releaseapplock @Resource ='a',
                                     @LockOwner = 'Session';

IF @ProcResult < 0
    RAISERROR('Failed to release application lock on %s. sp_releaseapplock returned %d', 16, 1, @PackageResourceName, @ProcResult);

When I ran this,  the release lock failing with the following error:

[Execute SQL Task] Error: Executing the query "DECLARE @ProcResult int = 0;

-- Release a previou..." failed with the following error: "Cannot release the application lock (Database Principal: 'public', Resource: 'a') because it is not currently held.
Failed to release application lock on a. sp_releaseapplock returned -999". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly.

When I use the same above tasks with same scripts in data tools 2010 its working fine. Any thing wrong in 2012 Data tools? 

Please advice. Tx in advance

Porus