C# webbrowser Open Local Web Page Error

Question

Hello to every one,

I am writing a simple web browser on c# 2008 express edition using WPF. It is working fine with www websites and display all content correctly. But if I want to open some local webpage - for instance "file://C:1/1.htm", it is save the webpage instead of displaying it. Im using windows7 x64. I made my application default programm for *.htm files, but it didn`t help. 
I will really appreciate any help.

Kind regards,
Pavel