Unable to run default XAML in Blend or VS2005

I open VS2005, Under the Visual C# node I select Net Framework 3.0, and then select Windows Application (WPF) from the templates on the right.

The following code is generated:

<Window x:Class="WindowsApplication8.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="WindowsApplication8" Height="300" Width="300"
>
<Grid>

</Grid>
</Window>

When I try to compile and run the app, I get the following error:

Cannot create instance of 'Window1' defined in assembly 'WindowsApplication8, Version=1.0.2613.23423, Culture=neutral, PublicKeyToken=null'. Exception has been thrown by the target of an invocation. Error in markup file 'Window1.xaml' Line 1 Position 9.

I create a new (Standard Exe - Visual C#) project in Expression Blend (Beta 2). And the following XAML is created by default:

<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xml:lang="en-US"
x:Class="UntitledProject6.Window1"
x:Name="Window"
Title="Window1"
Width="640" Height="480">

<Grid x:Name="LayoutRoot"/>
</Window>

I hit F5 to build and run the app, and the following error is generated:

Cannot create instance of 'Window1' defined in assembly 'UntitledProject6, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'. Exception has been thrown by the target of an invocation. Error in markup file 'Window1.xaml' Line 2 Position 2.