Unable to add attachment via Add Attachments to Form in ATF

[ShilpiN]

Through ATF I am able to open form, set the field values however when I am trying to attach any attachment using Add Attachments to Form step, I am getting error Invalid Table.

Same thing I am able to achieve manually with same user

Can someone help in this regards

[ShilpiN]

Attaching the screenshot of the steps used and following is the screenshot of the error :