flashbuilder exception in HaloBorder.as

Question

I am editing a very old project that has been created in flex 3. I am using flashbuilder 4.5 with flex 4.5.1 to do so.

When I try to run the projects I get an error in HaloBorder.as, wich is part of the sdk. Because it is part of the sdk I cannot edit the file. This is the error:

TypeError: Error #1009: Kan geen eigenschap of methode benaderen via een verwijzing naar een object dat null is.
    at mx.skins.halo::HaloBorder/http://www.adobe.com/2006/flex/mx/internal::drawBorder()[E:\dev\4.5.1\frameworks\projects\mx\src\mx\skins\halo\HaloBorder.as:596]
    at mx.skins.halo::HaloBorder/updateDisplayList()[E:\dev\4.5.1\frameworks\projects\mx\src\mx\skins\halo\HaloBorder.as:239]
    at mx.skins::ProgrammaticSkin/validateDisplayList()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\skins\ProgrammaticSkin.as:503]
    at mx.managers::LayoutManager/validateDisplayList()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\managers\LayoutManager.as:736]
    at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\managers\LayoutManager.as:801]
    at mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.5.1\frameworks\projects\framework\src\mx\managers\LayoutManager.as:1180]

As you can see, there is no way of knowing where the error occured in the project. The project uses mx to make up the layout. Could it have anything to do with this?

I have tried using any other theme, they work. but the layout of the entire project is broken.

If you need to see some part of the code to fix this, please tell me.

Thank you for your help.

Answer 1

The problem has been solved, there was an error in my css file.

The value of border-sides needs to be wrapped in quotes in the newer versions of flex.