I stripped out as much code as I could, and the error does still happen. I think the error has something to do with one of 2 files:
roles.mxml: <mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml" xmlns:test="components.*" xmlns:model="com.pinnacol.test.model.*" xmlns:comp="com.pinnacol.test.comparator.*" xmlns:px="com.pinnacol.test.component.*" creationComplete="model.initialize();" width="100%" height="100%"> <model:RoleModel id="model"/> <mx:TabNavigator width="100%" height="200" creationPolicy="all"> <mx:Canvas label="Functions ({model.detailFunctionCount})" width="100%" height="100%"> <test:roleFunctions id="functions" preinitialize="functions.roleModel=model"/> </mx:Canvas> etc. And roleFunctions.mxml: <mx:VBox xmlns:mx="http://www.adobe.com/2006/mxml" xmlns:model="com.pinnacol.test.model.*" xmlns:px="com.pinnacol.test.component.*" creationComplete="intialize()"> <mx:Script> <![CDATA[ public function intialize():void { trace("Initializing roleFunctions"); roleModel.addObserver(model); } ]]> </mx:Script> <model:RoleFunctionModel id="model" /> <model:RoleModel id="roleModel"/> In this case, the trace happens, but the addObserver call doesn't - I get the verify error as Flex tries to make the call. Steve