No, you can't use a DynamicResource in a Storyboard that is contained within a Style or ControlTemplate. In fact, you can't use a data binding expression either.
The story here is that everything within a Style or ControlTemplate must be safe for use across threads and the timing system actually tries to freeze the Style or ControlTemplate to make them thread-safe. However, if a DynamicResource or data binding expression is present, it is unable to freeze them.
For more info see: MSDN Link. Check out the 'Animate in a Style' and the 'Animate in a ControlTemplate' sections (this documentation page is rather long).
And for a workaround (at least for my scenario) see: WPF Forum Post.
Hope this helps someone. I've lost more than enough hair on it.
Cory
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