Spring Webflow: cannot get flow execution url at action phase of portlet

The following exception is thrown:

Caused by: java.lang.IllegalStateException: A flow execution action URL can only be obtained in a RenderRequest using a 
RenderResponse
    at org.springframework.webflow.context.portlet.PortletExternalContext.getFlowExecutionUrl(PortletExternalContext.java:2
06)
    at org.springframework.webflow.engine.impl.RequestControlContextImpl.getFlowExecutionUrl(RequestControlContextImpl.java
:178)
    at org.springfram开发者_JAVA百科ework.webflow.mvc.view.AbstractMvcView.render(AbstractMvcView.java:172)
    at org.springframework.webflow.engine.ViewState.render(ViewState.java:282)
    at org.springframework.webflow.engine.ViewState.refresh(ViewState.java:241)
    at org.springframework.webflow.engine.ViewState.resume(ViewState.java:219)
    at org.springframework.webflow.engine.Flow.resume(Flow.java:545)
    at org.springframework.webflow.engine.impl.FlowExecutionImpl.resume(FlowExecutionImpl.java:259)
    ... 62 more

It seems for me like resuming execution of flow at action phase tries to do render phase's stuff. Any ideas?

The error was in not provding eventId in request because of syntax error.