An exception occurred in nintex -- workflow task.

Problem description:

I used the request approval action in nintex. An error occurred after the workflow was started. After searching the log, I found the following information:

10/13/2011 pm	Error	System Account	Exception has been thrown by the target of an invocation.	Error
10/13/2011 pm	Error	System Account	Cannot find a corresponding human workflow task id for this task.	Error

Solution: Delete the currently bound workflow task list, re-create the workflow task list, and bind it. Everything works.