hi!
I have been getting "Warning 2 Validation (XHTML 1.0 Transitional): Element 'header' is not supported" when I ran a downloaded template.
The website ran perfectly but showing warning at compile time. I deleted "ReflectedSchemes" folder(http://www.gotknowhow.com/articles/fix-validation-element-not-supported-visual-studio-2010) but it didn't worked for me.
Best Regrads,
Shashikant