InfoPath Dev

I have an InfoPath form that contain onSubmitRequest function (In .Net CodeForm- C#).
In the function I'm create an object of WebService (which is web reference in my .NET project) that get the form's values and enter them into database.
When I run my form as a preview form, It's all work well. But when I publish the form and run it I get this Error:

"infoPath cannot submit the form.
The onSubmitRequest event handler did not work.
Request for the permission of type System.Net.WebPermission"

Why it's happen and how to fix it????

Hi again,
You need to buy our book and read chapter 8. ;) This is actually a rather involved topic, but short answer is that you'll need to change your security or give the form greater permissions or change the code to do something that doesn't require full trust.
Good luck!