Basically I am upgrading from 1.1 to .NET 3.5 SP1 and replacing an old .NET 1.1 WebForms application with its newer .NET 3.5 version.
I have done this exact same process on 5 different (relatively) identical boxes and it worked on every single one except for the current one.
Here when I try to navigate to the home page I get an error: Parser Error Message: unkown server tag asp:UpdateProgress You can see the full error here: http://pastebin.com/f460e58bd
Since UpdateProgress is in System.Web.Extensibility.dll I checked the GAC - it is not installed. So I tried moving it manually into the applications bin directory - this didn't fix it. I then tried copying gacutil to the machine and installing the file to the GAC manually, the install succeeded but my application still is failing and I'm out of ideas.
Does anyone have any idea what else I can try?
The server is a Windows 2003 Server SP1.
Try adding this to the bottom of your web.confg:
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="System.Web.Extensions" publicKeyToken="31bf3856ad364e35"/>
<bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="System.Web.Extensions.Design" publicKeyToken="31bf3856ad364e35"/>
<bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>
</dependentAssembly>
</assemblyBinding>
</runtime>
If it works then it's a problem with your pages looking for the specific older version of the System.Web.Extensions DLL. A recompile of the DLLs that reference System.Web.Extensions should fix it also.
Also here's the much more common error people see, and a better Google search to get you pointed in the right direction since the ScriptManager is usually the first System.Web.Extensions control parsed.