[Zope] Syntax Error

Well, it's the end of my first day of Zope programming and I like it :-) I've written a nice app that helps me manage my contacts much quicker than I could in straight Python but there is one aspect that is driving me nuts! If I make a mistake when typing and then I click save it often gives me an error page and won't let me go BACK and change what I have just typed. Is this normal Zope behaviour? Simon