I have developed a simple approval process using JBPM.

Basically I have a home page for the approver, which displays a list of documents that needs to be approved. 

<h:dataTable value="#{taskInstanceList"} var="task" ... >)

On each row, i also put in an s:link tag so I can direct the approver to another page where he can review and where the approve button would be.

<s:link ... taskInstance=#{task}> 

However, I when I go to the document page, I put in an outputText with a value of taskInstance.id for tracing purposes, and noticed that is not display anything or is null.

<h:outputText value="#{taskIntance.id}"> 

Also on the document page, I have the Approve button which calls a method ApproveMe which has an annotation BeginTask.

...
...
@BeginTask
public String ApproveMe() {

//doSomethingToApprove

}
...

I get an Exception saying

task/process id may not be null

So I think, the taskInstance variable or pointer got lost along the way.

Any Ideas?