I've lately changed focus from MOSS 2007 to work with Microsoft Dynamics CRM solutions, anyhow. As Microsoft doesn't use the .NET 3.5 web extensions AJAX functionalities in CRM 4, and that is something that you may like to use in your ISV solutions, you need to change the "C:\Program Files\Microsoft Dynamics CRM\CRMWeb\web.config" to include all the references to the .NET 3.5 libraries. As you may know changing the web.config is not a supported customization, as after an upgrade your changes won't be there. So I have a plan of writing a small consoleapp that will add the changes to the web.config but until then here is a web.config with them included.
web.config for Microsoft CRM v4.0.7333.145 with AJAX enabled
web.config (3,35 KB)