InfoPath Dev

Thanks for your help, but we found out that it isn't the form that is wrong. It's something wrong on the Sharepoint Application Site. One the one SharePoint it runs without problems, but on the other it doesn't. We compared the settings, there wasn't something different until yet.

I have the following problem: A colleague of mine created a form in InfoPath and the end-user has to fill it in with his browser, but it don't works. I think he did forget to mark that only browser compatible features has to be activated at the very beginning. Is there a way to resolve that? I don't want to recreate it, because ...