Even i am facing the same issue. Which "input" setting of xfaform variable are you asking for?
Whether it is the checking of "input" check box of the Process Variable category, while creating xfaform?
or, assigning the variable to the Input column of User's Assign Task operation?
I experience the same error in LC ES2. I was struck with this issue.
Can anyone help me on this.
In Detail: I jus designed a sample workflow with 2 Assign Task services in it along with the default other services present.
I was able to initiate the form from the workspace and am able to submit it as a worklist item. But when i tried to open it from the worklist after receiving, am facing the same issue ALC-WKS-007-040.
I donno how to proceed after this..