RTE when PopUpManager.createPopUp is called

Steps to reproduce:
1. Import the attached project.
2. Click the "Create pop up" Button

Actual Results:
Error: Skin for MyWindow19.Scroller20 cannot be found.
at spark.components.supportClasses::SkinnableComponent/attachSkin()[C:\opensource\sdk\trunk\frameworks\projects\spark\src\spark\components\supportClasses\SkinnableComponent.as:629]
at spark.components::Scroller/attachSkin()[C:\opensource\sdk\trunk\frameworks\projects\spark\src\spark\components\Scroller.as:834]
at spark.components.supportClasses::SkinnableComponent/validateSkinChange()[C:\opensource\sdk\trunk\frameworks\projects\spark\src\spark\components\supportClasses\SkinnableComponent.as:404]
at spark.components.supportClasses::SkinnableComponent/createChildren()[C:\opensource\sdk\trunk\frameworks\projects\spark\src\spark\components\supportClasses\SkinnableComponent.as:367]
at mx.core::UIComponent/initialize()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\core\UIComponent.as:7254]
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\core\UIComponent.as:7145]
at mx.core::UIComponent/addChildAt()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\core\UIComponent.as:6851]
at spark.components::Group/addDisplayObjectToDisplayList()[C:\opensource\sdk\trunk\frameworks\projects\spark\src\spark\components\Group.as:1823]
at spark.components::Group/http://www.adobe.com/2006/flex/mx/internal::elementAdded()[C:\opensource\sdk\trunk\frameworks\projects\spark\src\spark\components\Group.as:1412]
at spark.components::Group/setMXMLContent()[C:\opensource\sdk\trunk\frameworks\projects\spark\src\spark\components\Group.as:512]
at spark.components::Group/createChildren()[C:\opensource\sdk\trunk\frameworks\projects\spark\src\spark\components\Group.as:734]
at mx.core::UIComponent/initialize()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\core\UIComponent.as:7254]
at MyWindow/initialize()
at mx.managers.systemClasses::ChildManager/childAdded()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\managers\systemClasses\ChildManager.as:189]
at mx.managers::SystemManager/http://www.adobe.com/2006/flex/mx/internal::rawChildren_addChildAt()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\managers\SystemManager.as:1963]
at mx.managers::SystemManager/addChildAt()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\managers\SystemManager.as:1595]
at mx.managers::SystemManager/addChild()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\managers\SystemManager.as:1578]
at mx.managers::PopUpManagerImpl/addPopUp()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\managers\PopUpManagerImpl.as:341]
at mx.managers::PopUpManagerImpl/createPopUp()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\managers\PopUpManagerImpl.as:232]
at mx.managers::PopUpManager$/createPopUp()[C:\opensource\sdk\trunk\frameworks\projects\framework\src\mx\managers\PopUpManager.as:135]
at Module1/createPopUp()[C:\ws\wstrunk\CreatePopUpManager\src\Module1.mxml:15]
at Module1/___Module1_Button1_click()[C:\ws\wstrunk\CreatePopUpManager\src\Module1.mxml:28]

Expected Results:
No RTE.

Workaround (if any):