using dhtmlxConnector for PHP v.1.5
throwing error: Missing argument 1 for MultitableTreeRenderStrategy::get_level()
traced to TreeMultitableConnector::xml_start() line 31: return "<tree id=…, $this->render->get_level() …
believe the call to get_level() should be referenced by self ($this->) only and not “render->” as MultitableTreeRenderStrategy does not contain get_level method w/no parameters
corrected line 31: return "<tree id=…, $this->get_level() …
once the change is made the code works correctly