You can only attach images to forum posts and I suppose that is why the attachment you mentioned is missing. Please open a new support ticket for the same problem and send me the test project in it.
In the meantime, please make sure that you are using TwoWay binding for the following properties - PeriodStart/PeriodEnd. VisiblePeriodStart/VisiblePeriodEnd, SelectionStart/SelectionEnd. This is required because of the coercing mechanism of RadTimeBar.
All the best,
the Telerik team