Fatal error: Call to a member function setObjectSID() on a non-object in /var/www/chemiewerkt/system/lib/orm/ObjectProperty.php on line 137

Call Stack:
    0.0004     148100   1. {main}() /var/www/chemiewerkt/index.php:0
    0.7727    6043456   2. SJB_Request->execute() /var/www/chemiewerkt/index.php:81
    0.7753    6045192   3. SJB_System::getPage() /var/www/chemiewerkt/system/core/Request.php:228
    0.7756    6058260   4. SJB_PageConstructor::getPage() /var/www/chemiewerkt/system/core/System.php:331
    0.8264    6401776   5. SJB_System::executeFunction() /var/www/chemiewerkt/system/core/PageConstructor.php:43
    0.8264    6401800   6. SJB_ModuleManager->executeFunction() /var/www/chemiewerkt/system/core/System.php:189
    0.8311    6515008   7. SJB_Classifieds_DisplayListing->execute() /var/www/chemiewerkt/system/core/ModuleManager.php:141
    0.8442    6624048   8. SJB_ListingManager::getObjectBySID() /var/www/chemiewerkt/system/user-scripts/classifieds/display_listing.php:82
    1.0666    7860584   9. SJB_Object->setSID() /var/www/chemiewerkt/system/lib/classifieds/Listing/ListingManager.php:56
    1.0666    7860616  10. SJB_ObjectDetails->setObjectSID() /var/www/chemiewerkt/system/lib/orm/Object.php:34
    1.0667    7860780  11. SJB_ObjectProperty->setObjectSID() /var/www/chemiewerkt/system/lib/orm/ObjectDetails.php:41