I haven't been able to get the 'Validation Show If' server behaviour to work. I've tried normal text, an image and text in a layer for the error message. When you view the page, the error message is not hidden (text, image or layer). I've set the layers visibility to hidden but it also doesn't show when submitted.
I have however solved it for now, by re-inserting a redirect to a failed page and then just binding the elements to the first page.