Well, if I open the main.xml from the Blue Steel skin in IE6 I receive the following:
Duplicate attribute. Error processing resource 'file:///C:/Program Files/J River/Media Center/MegaSkins/Blue Steel/main.xml'. Line 9, Position 195
<Entry Name="TopBorder" Bitmap="MainFrame_TopBorder.bmp" NumberImages="1" TransColor="FF00FF" Margins="204,1,64,1" DrawMode="REGION_E_HSTRETCH,REGION_E_VTILE,REGION_B_STRETCH,REGION_H_STRETCH" TransColor="FF00FF" />
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I had written this off as IE just not noticing that, while TopBorder does exist in multiple places, they are all sub-items of other non-duplicate items (MainFrame, Frame, etc). I assume it would have the same problem with BottomBorder, RightBorder, etc.
I hope that's all it is, because I'd really like to use a pre-built parser if possible.
I've written this in C#.