smartpart with AJAX

I've installed smartpart with AJAX, but when i try to add this webpart into the page, MOSS returned an error saying that the webpart is no longer there.

After a bit of searching, i've found in within codeplex discussion itself saying that adding these into the <runtime> node of the web.config. It worked.

<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>