Sharepoint 2010 workflow failes with "<nativehr>0x80070057</nativehr><nativestack></nativestack>"

Question

I have created a simple Sharepoint 2010 site workflow that creates and manipulates tasks in a list.
All my activities execute properly, but when the workflow is about to get to the end (the red point in the diagram :)) some nasty exception happens.
Even with the exception the workflow is marked as complete.

I have tried to remove the last activities from the workflow because I thought they are causing the trouble, but the problem persists (this is the reason I think the problem is the finalization of the workflow itself and not my activities).

Have you encountered such problem and if you had how can I solve it?

Here are exception details:
Exception: System.Workflow.Runtime.Hosting.PersistenceException
InnerException: System.ArgumentException
InnerExceptionMessage: <nativehr>0x80070057</nativehr><nativestack></nativestack>
Message: <nativehr>0x80070057</nativehr><nativestack></nativestack>
Stack Trace:

    at System.Workflow.Runtime.WorkflowExecutor.Persist(Activity dynamicActivity, Boolean unlock, Boolean needsCompensation)
    at System.Workflow.Runtime.WorkflowExecutor.System.Workflow.ComponentModel.IWorkflowCoreRuntime.PersistInstanceState(Activity activity)
    at System.Workflow.ComponentModel.Activity.MarkClosed()
    at System.Workflow.ComponentModel.Activity.ReleaseLockOnStatusChange(IActivityEventListener\`1 eventListener)
    at System.Workflow.ComponentModel.FaultAndCancellationHandlingFilter.SafeReleaseLockOnStatusChange(ActivityExecutionContext context)
    at System.Workflow.ComponentModel.FaultAndCancellationHandlingFilter.OnEvent(Object sender, ActivityExecutionStatusChangedEventArgs e)
    at System.Workflow.ComponentModel.ActivityExecutorDelegateInfo\`1.ActivityExecutorDelegateOperation.Run(IWorkflowCoreRuntime workflowCoreRuntime)
    at System.Workflow.Runtime.Scheduler.Run()