None of the include files have template data, no. To be honest, I've never used Dreamweaver templates period.
The include files simply have, for example, Google Analytics code, or a CSS Menu Writer menu, or a simple footer (text and links).
I've deleted the Dreamweaver cache file, and restarted, but still no joy. Do you think uninstalling / reinstalling the Validation Toolkit extension would solve it?
Like you, I can't see why this error would be appearing.
I'm using Dreamweaver 8. Would that be the problem? Thing is, I haven't changed anything recently and Validation Toolkit was working fine.
It's all a bit odd really.