system.web.ui.page not installed

[wize]

Hello

I'm getting an error when I try to create a new ASP.NET Application

"base class system.web.ui.page not installed"
I see the HTML code for the new page but cannot see the designer (no buttons
in bottom left to allow me to switch views)

I have found references to this error on the web but I have not found a
solution. If there's a class not installed then can I repair my
installation

W

Windows XP SP2
..NET Framework 1.1
..NET 2003 Enterprise Architect