Nintex Workflow 2010 Requst Approval task, set outcome from c# code

Hi,

when I try to set approval outcome from code (Request Approval action task), I get the following exceptions in ULS Viewer:

Exception1:

: Nintex.Workflow.NWHumanApprovalException: Unauthorized attempt to update approval task by SEEU\aa08424. The response has not been recorded. (Build:2370)

Exception2:

(https://test.seeu.edu.mk/sites/test/_layouts/NintexWorkflow/preview.aspx?ListId=64e30e91-4d26-48d5-8f0b-e54c0eba61bc&ItemId=53&InstanceId=c4659263-7ba2-4372-a866-8cc5534966b7): Nintex.Workflow.NWActionExecutionException: Error in request approval action. ---> Nintex.Workflow.NWHumanApprovalException: Unauthorized attempt to update approval task by SEEU\aa08424. The response has not been recorded.    

 at Nintex.Workflow.HumanApproval.ApprovalTask.ProcessResponse(User user, String comment, Outcome outcome, Int32 taskListItemId)    

 at Nintex.Workflow.Activities.ApprovalActivityInternal2.ChildCompleted(Object sender, ReplicatorChildEventArgs e)    

 at System.Workflow.ComponentModel.Activity.RaiseGenericEvent[T](DependencyProperty dependencyEvent, Object sender, T e)    

 at System.Workflow.Activities.ReplicatorActivity.HandleStatusChange(ActivityExecutionContext executionContext, ActivityExecutionStatusChangedEventArgs e, ReplicatorSubscriber subscriber)    

 at System.Workflow.ComponentModel.ActivityExecutorDelegateInfo`1.ActivityExecutorDelegateOperation.Run(IWorkflowCoreRuntime workflowCoreRuntime)    

 at System.Workflow.Runtime.Scheduler.Run()     -

 -- End of inner exception stack trace --- (Build:2370)

Exception3:

WinWF Internal Error, terminating workflow Id# c4659263-7ba2-4372-a866-8cc5534966b7

Exception4:

Nintex.Workflow.NWHumanApprovalException: Unauthorized attempt to update approval task by SEEU\aa08424. The response has not been recorded.    

 at Nintex.Workflow.HumanApproval.ApprovalTask.ProcessResponse(User user, String comment, Outcome outcome, Int32 taskListItemId)    

 at Nintex.Workflow.Activities.ApprovalActivityInternal2.ChildCompleted(Object sender, ReplicatorChildEventArgs e)    

 at System.Workflow.ComponentModel.Activity.RaiseGenericEvent[T](DependencyProperty dependencyEvent, Object sender, T e)    

 at System.Workflow.Activities.ReplicatorActivity.HandleStatusChange(ActivityExecutionContext executionContext, ActivityExecutionStatusChangedEventArgs e, ReplicatorSubscriber subscriber)    

 at System.Workflow.ComponentModel.ActivityExecutorDelegateInfo`1.ActivityExecutorDelegateOperation.Run(IWorkflowCoreRuntime workflowCoreRuntime)    

 at System.Workflow.Runtime.Scheduler.Run()

 and at Workflow History:

Workflow History

The following events have occurred in this workflow.

Date Occurred

Event Type

User ID

Description

Outcome

5/8/2013 2:09 PMErrorSystem AccountNWTest failed to run.

5/8/2013 2:12 PMTask CompletedSEEU\aa08424(SEEU\aa08424) ReSubmitted by student...Approved

5/8/2013 2:12 PMCommentError in request approval action. Unauthorized attempt to update approval task by SEEU\aa08424. The response has not been recorded.Error

5/8/2013 2:12 PMErrorSystem AccountAn error has occurred in NWTest.