internal error creating petition after authentication

/registry/co_petitions/add/coef:1/co:2

When accessing the path above I was prompted for authentication and then afterwards received an error. The stack trace is

Stack Trace:
#0 /opt/comanage/trunk/app/Controller/Component/RoleComponent.php(281): RoleComponent->identifierIsCmpAdmin('skoranda@shibbi...')
#1 /opt/comanage/trunk/app/Controller/CoPetitionsController.php(322): RoleComponent->calculateCMRoles()
#2 /opt/comanage/trunk/app/Controller/CoPetitionsController.php(172): CoPetitionsController->isAuthorized()
#3 [internal function]: CoPetitionsController->beforeFilter(Object(CakeEvent))
#4 /opt/comanage/trunk/lib/Cake/Event/CakeEventManager.php(248): call_user_func(Array, Object(CakeEvent))
#5 /opt/comanage/trunk/lib/Cake/Controller/Controller.php(670): CakeEventManager->dispatch(Object(CakeEvent))
#6 /opt/comanage/trunk/lib/Cake/Routing/Dispatcher.php(184): Controller->startupProcess()
#7 /opt/comanage/trunk/lib/Cake/Routing/Dispatcher.php(162): Dispatcher->_invoke(Object(CoPetitionsController), Object(CakeRequest), Object(CakeResponse))
#8 /opt/comanage/trunk/app/webroot/index.php(96): Dispatcher->dispatch(Object(CakeRequest), Object(CakeResponse))
#9