Better error message when parser can't find a widget. Refs #2976.
Better error message when parser can't find a widget.
Refs #2976.

git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@8532 560b804f-0ae3-0310-86f3-f6aa0a117693

redaktor/deliteful