Thanks for including the pages in your post. I was testing with your pages and I could not get the error to occur for me. If you could please post back and include a little more info about how you are applying the reformatting of the date. Are you using the validation wizard to apply the validation or are you using the server validations that are on the page? Please let me know exactly how you are applying the validations so that I can create the problem the same as you are experiencing it. Also, what are the values you are entering into the form when the error occurs? It seems that there is some part of this that I'm not doing the same as you since I do not get the same result.