[flexcoders] Help with error message

[markgoldin_2000]

What exaclty this means:
TypeError: Error #2007: Parameter antiAliasType must be non-null.
at flash.text::TextField/set antiAliasType()
        at mx.core::UITextFormat/measure()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UITextFormat.a
s:459]
        at mx.core::UITextFormat/measureText()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UITextFormat.a
s:385]
        at mx.core::UIComponent/measureText()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UIComponent.as
:6151]
        at yardmodel.modulecode::destinationGrid/set assignBlocks()
[D:\testarea\beltrailway\flexversions\src\yardmodel\modulecode\destina
tionGrid.as:45]
        at mx.core::ClassFactory/newInstance()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\ClassFactory.a
s:153]
        at 
mx.controls.advancedDataGridClasses::AdvancedDataGridBase/http://www.a
dobe.com/2006/flex/mx/internal::columnItemRenderer()
[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\control
s\advancedDataGridClasses\AdvancedDataGridBase.as:1415]
        at 
mx.controls::AdvancedDataGridBaseEx/http://www.adobe.com/2006/flex/mx/
internal::getMeasuringRenderer()
[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\control
s\AdvancedDataGridBaseEx.as:2004]
        at mx.controls::AdvancedDataGridBaseEx/measureItems()
[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\control
s\AdvancedDataGridBaseEx.as:6985]
        at mx.controls::AdvancedDataGridBaseEx/commitProperties()
[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\control
s\AdvancedDataGridBaseEx.as:1973]
        at mx.controls::AdvancedDataGrid/commitProperties()
[C:\Work\flex\dmv_automation\projects\datavisualisation\src\mx\control
s\AdvancedDataGrid.as:2209]
        at mx.core::UIComponent/validateProperties()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UIComponent.as
:5670]
        at mx.managers::LayoutManager/validateProperties()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\managers\LayoutMana
ger.as:519]
        at mx.managers::LayoutManager/doPhasedInstantiation()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\managers\LayoutMana
ger.as:669]
        at Function/http://adobe.com/AS3/2006/builtin::apply()
        at mx.core::UIComponent/callLaterDispatcher2()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UIComponent.as
:8460]
        at mx.core::UIComponent/callLaterDispatcher()
[E:\dev\3.0.x\frameworks\projects\framework\src\mx\core\UIComponent.as
:8403]

Thanks for looking into it.