Problem with workflow engine

Hi everybody, I am pretty new here.
I appreciate the team for this great tool. Thanks a lot.
I have a serious and urgent problem here and I don't know whether it is an
installation problem.
I tried several different installation configurations but could not get
workflow running.
I can not change the publish status of any content to online. The workflow
status remains red. The content goes into locked state.
What am I doing wrong?

Jahia 5.0.1. r16138
Postgres 8.1
Tomcat

Thanks a lot
Ferhat Akcin