Hi Arihant,
The error you are getting is because you forgot to add the field to the table from the BAPI_WRAPPER that is bringing this data from the SAP backend.
I attach an image with the table you should enhance.
Then, you have to modify the ABAP class handler, in order to retrieve the field data and populate the BAPI Table.
Finally, when finishing editing, remember to restart the Agentry Server so the changes take effect in the server.
You can test if the complex table field is populated, using the ATE (Agentry Test Enviorment).
Go to: Inspect>Complex Tables
Try this, and let me know your results.
Best Regards,
Emanuel