SP for Batch Making

Hi experts i Created the following SP

--/*Block Batch Making when Batch Attribute 1 is Null*/

IF @transaction_type IN ('U') AND @Object_type = '10000044'

BEGIN

IF EXISTS (SELECT T0.AbsEntry FROM OBTN T0

WHERE T0.MnfSerial is null

and T0.AbsEntry = @list_of_cols_val_tab_del)

BEGIN

SELECT @Error = 525, @error_message = 'Select Job No in Batch Attribute 1'

END

END

my goal is to block batch making when use did not select any value in Batch Attribute 1 field but this SP is not working

Can any one guide me what am i missing here?

Regards

Jamil Siddiqui