Could not load type "System.Web.UI.IScriptManager"

Hi,

I have developped an application in VS2008, using .NET 3.5
I'm using some Devexpress and Ms-AJAX controls and all works fine on the
DEV-machine (as it always does ;-) )
Now that it's deployed on the webserver I get the error as pasted in below:

I've asked the web-hosting company to install the .NET Framework version 3.5
and they did but for some reason I get this weird error. I've also seen
another post about this (8-jan-2008) but there was no real solution there so
I try again right here.


Hope someone can help me out here...

TIA,
Jurjen


Server Error in '/' Application.
------------------------------------------------------------ --------------------

Parser Error
Description: An error occurred during the parsing of a resource required to
service this request. Please review the following specific parse error
details and modify your source file appropriately.

Parser Error Message: Could not load type 'System.Web.UI.IScriptManager'
from assembly 'System.Web, Version=2.0.0.0, Culture=neutral,
PublicKeyToken=b03f5f7f11d50a3a'.

Source Error:

Line 10: <%@ Register assembly="DevExpress.Web.ASPxEditors.v7.3,
Version=7.3.6.0, Culture=neutral, PublicKeyToken=9b171c9fd64da1d1"
namespace="DevExpress.Web.ASPxEditors" tagprefix="dxe" %>
Line 11:
Line 12:
Line 13:
Line 14: