Workflow activity error on voting

Hi,

I'm getting this error during a task completition

I find in logs the AML that caused error:

<AML>
<Item type="Activity" action="EvaluateActivity">
<Activity>B500D2569FC54E9AAA7266D3BF9C80E0</Activity>
<ActivityAssignment>1D5158BBDA364998B43403E30243E3A7</ActivityAssignment>
<Paths>
<Path id="1A9BF5EE8BAB4D5885D0680C931ADB81"><![CDATA[Review]]></Path>
</Paths>
<DelegateTo>0</DelegateTo>
<Tasks>
<Task id="44FD3E46B1DC4F21B3CCBD517B266970" completed="1">
</Task>
<Task id="C6B7EC937DD6470B9D910BDA68D8AE12" completed="1">
</Task>
</Tasks>
<Variables>
</Variables>
<Authentication mode="">
</Authentication>
<Comments>
</Comments>
<Complete>1</Complete>
</Item>
</AML>

I try also to apply this AML using nash but error is the same "An item with the same key has already been added" how I can complete the WF activity?

Thanks