I have problem connectiong the game

Just after choosing the server, i got the message about a System Null reference exception.

it's about something
System.Windows.Forms.UnsafeNative.Methods.CallWind owProc (IntPtr wndProc, IntPtr hWnd etc...

i work on a Vista system

So far i ve tried

uninstall/reinstall DDO
Uninstall/reinstall Net Framework (tricky for the 1.1)
Lanching in safe mode
rebooting my modem

nothing works ....

please help me