Fail to use Kettle Data source in my CDE dashboard

Hi everyone,


I am using apache kafka consumer to read message from broker.
After that, i add some step to process above messages to get desired result.
I save all step to a transformation file and import it to CDE dashboard as a data source using "Kettle over kettleTransFromFile".
But when i run the dashboard, it show an error as following: Error processing component (temperature_bar).
temperature_bar is a CCC bar chart component in my dashboard. It use the above Kettle tranformation file as data source.
I know the Kettle data source cause the problem but can't figure out how to fix it.
Please help me to solve this problem.
Sorry for my bad english


Many thanks,
Hoang Anh.