ScriptManager & Rad controls

[M Iftekharul]

I had a solution running with Rad controls in .Net framework 2.0. As I've updated my solution to framework 3.5, I'm facing this error in my page with RadWindow:

The control with ID 'radWManager' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.

But the ScriptManager is there before the "RadWManager", which is a RadWindowManager. What can be the case here?