Java EE (Java Enterprise Edition) General Discussion

I'm getting an error message when I submit a form.
I used the <h:message> tag to display the detailed and summary messages.
They both said: Validation Error: Value is not valid

Is it me, or is this completely useless?

What value did the validator receive?
That one piece of information would allow me to track down the bug.
Does anyone have any good tips on debugging jsf errors?