flash.text.engine::ElementFormat/set fontSize()

With FB compiler prop checked as Use Flash Text Engine in MX Components, i am getting the below error. When i debug, fontSize is passed as negative value to the below line of code in FTETextField.as

elementFormat.fontSize = Number(_defaultTextFormat.size);

The error is shown below.

ArgumentError: Error #2004: One of the parameters is invalid.
at flash.text.engine::ElementFormat/set fontSize()
at mx.core::FTETextField/createElementFormat()[E:\dev\hero_private\frameworks\projects\spark\src\mx\core\FTETextField.as:2668]
at mx.core::FTETextField/validateNow()[E:\dev\hero_private\frameworks\projects\spark\src\mx\core\FTETextField.as:2529]
at mx.core::FTETextField/setTextFormat()[E:\dev\hero_private\frameworks\projects\spark\src\mx\core\FTETextField.as:2382]
at mx.core::UIFTETextField/validateNow()[E:\dev\hero_private\frameworks\projects\spark\src\mx\core\UIFTETextField.as:2253]
at mx.core::UIFTETextField/set nestLevel()[E:\dev\hero_private\frameworks\projects\spark\src\mx\core\UIFTETextField.as:1526]
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::addingChild()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7444]
at mx.core::UIComponent/addChild()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7152]
at mx.controls::Button/createChildren()[E:\dev\hero_private\frameworks\projects\mx\src\mx\controls\Button.as:1614]
at mx.core::UIComponent/initialize()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7624]
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7485]
at mx.core::UIComponent/addChild()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7166]
at mx.controls::ComboBase/createChildren()[E:\dev\hero_private\frameworks\projects\mx\src\mx\controls\ComboBase.as:1162]
at customcomponents::CustomAutoText/createChildren()[D:\XtendSpark\XtendSparkArch-Sp2\src\customcomponents\CustomAutoText.as:194]
at mx.core::UIComponent/initialize()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7624]
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7485]
at mx.core::UIComponent/addChildAt()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7189]
at spark.components::Group/addDisplayObjectToDisplayList()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:2037]
at spark.components::Group/http://www.adobe.com/2006/flex/mx/internal::elementAdded()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:1628]
at spark.components::Group/setMXMLContent()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:633]
at spark.components::Group/createChildren()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:855]
at mx.core::UIComponent/initialize()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7624]
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7485]
at mx.core::UIComponent/addChildAt()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7189]
at spark.components::Group/addDisplayObjectToDisplayList()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:2037]
at spark.components::Group/http://www.adobe.com/2006/flex/mx/internal::elementAdded()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:1628]
at spark.components::Group/setMXMLContent()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:633]
at spark.components::Group/createChildren()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:855]
at mx.core::UIComponent/initialize()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7624]
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7485]
at mx.core::UIComponent/addChildAt()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7189]
at spark.components::Group/addDisplayObjectToDisplayList()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:2037]
at spark.components::Group/http://www.adobe.com/2006/flex/mx/internal::elementAdded()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:1628]
at spark.components::Group/setMXMLContent()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:633]
at spark.components::Group/createChildren()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:855]
at mx.core::UIComponent/initialize()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7624]
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7485]
at mx.core::UIComponent/addChildAt()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7189]
at spark.components::Group/addDisplayObjectToDisplayList()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:2037]
at spark.components::Group/http://www.adobe.com/2006/flex/mx/internal::elementAdded()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:1628]
at spark.components::Group/setMXMLContent()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:633]
at spark.components::Group/set mxmlContent()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\Group.as:573]
at spark.components::SkinnableContainer/set mxmlContent()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\SkinnableContainer.as:657]
at spark.components::SkinnableContainer/createDeferredContent()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\SkinnableContainer.as:1050]
at spark.components::SkinnableContainer/createContentIfNeeded()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\SkinnableContainer.as:1078]
at spark.components::SkinnableContainer/createChildren()[E:\dev\hero_private\frameworks\projects\spark\src\spark\components\SkinnableContainer.as:885]
at mx.core::UIComponent/initialize()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7624]
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7485]
at mx.core::Container/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:3974]
at mx.core::Container/addChildAt()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:2618]
at mx.core::Container/addChild()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:2534]
at mx.core::Container/createComponentFromDescriptor()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:4396]
at mx.core::Container/createComponentsFromDescriptors()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:4183]
at mx.core::Container/createChildren()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:3189]
at mx.core::UIComponent/initialize()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7624]
at mx.core::Container/initialize()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:3131]
at common.controller::titleManager/initialize()
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\framework\src\mx\core\UIComponent.as:7485]
at mx.core::Container/http://www.adobe.com/2006/flex/mx/internal::childAdded()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:3974]
at mx.core::Container/addChildAt()[E:\dev\hero_private\frameworks\projects\mx\src\mx\core\Container.as:2618]
at newXtend/titleBarChangings()[D:\XtendSpark\XtendSparkArch-Sp2\src\newXtend.mxml:1327]
at newXtend/init()[D:\XtendSpark\XtendSparkArch-Sp2\src\newXtend.mxml:334]
at newXtend/___newXtend_WindowedApplication1_creationComplete()[D:\XtendSpark\XtendSparkArch-Sp2\src\newXtend.mxml:10]
at flash.events::EventDispatcher/dispatchEventFunction()