Mini6410 image + .NET CF 2.0

I've built an image without .NET Compact Framework 2.0 and install
"NETCFv2.wce5.armv4i.cab" after its start.
My program runs well.

After that I've built an image with .NET Compact Framework 2.0.
When I start my program get message: MissingMethodException, Could not load
type 'System.Windows.Form'...

What is missing in this built?

Without giving too much detail, I'm having the same problem with mini2440.

Still diagnosing though... I think I'm starting the app too early in the
boot process but it could be something else.

If anyone ran into the same problem, please help :)