When I have added following line just above the Webservice class declaration, the Cascading Dropdown functionality is started working for me.
It's amazing. But soon I noticed some limitations with Cascading Dropdown. When i tried to populate large amount of data it again started throwing [Method Error 500] error. This error is not related to the number items in the drop down. I think this is related to amount of data being populated in the dropdown. The functionality works if I have limited data. But if the no of item/ size of item increase the problem starts.
Does anyone know solution to this problem? Your immediate help is much appreciated.