when posting a question, please also give us following information:
Which simulator version do you use? What is the version or where and when did you download it?
What is your configuration file when the error occurs? It helps if you also paste the config file
Often, problems occur due to the usage of an outdated version of the simulator, so: use the newest simulator version!
You find the code at Google Code: http://code.google.com/p/peerfactsimkom-community/
You can now download the newest version of PeerfactSim.KOM – Community Edition under this link: https://peerfactsimkom-community.googlecode.com/archive/master.zip
For questions regarding the simulator, please visit http://www.peerfact.org