It can't even be published as a browser form unless it only has browser form capabilities. There are very few restrictions on browser forms in 2010, so I doubt it's a case of having incompatible features. Even if it were the case, he wouldn't have been able to publish the form to begin with. It would have given design checker errors, and the publish would have failed. However, if you're saying that your user doesn't have InfoPath 2010, and the developer created it as a Rich Client form, then that was just a mistake on the developer's part. You wouldn't develop and publish a client form if not all of your users have InfoPath 2010 - that would make no sense. If that's what happened, then you need to change the compatibility to browser form, and if it's got 2010 features, then you have to be using SharePoint 2010. Otherwise, if you only have SharePoint 2007, then this form must be completely changed so that it only has 2007 features.
So, what you need to tell us is EXACTLY what you mean by "but it don't works." That is very little information for us, and there are many reasons for a form not to work for an individual. Please tell us exactly what happens when that end user tries to open a new form. Also, what happens when you open it?