Issue with ExclusiveChoice node

[bretrzaun]

I have a workflow defined in XML. After upgrading the Workflow component from 1.3 to 1.4 I get an ezcWorkflowInvalidWorkflowException exception when trying to load the XML definition.

Message: Node of type "ExclusiveChoice" has less outgoing nodes than required.

  <node id="55" type="ExclusiveChoice">
    <condition type="Variable" name="choice">
      <condition type="IsString"/>
      <outNode id="80"/>
    </condition>
    <condition type="Not">
      <condition type="Variable" name="choice">
        <condition type="IsString"/>
        <outNode id="60"/>
      </condition>
    </condition>
  </node>

What is wrong with this definition ? Who do I have to change to make it work again ?