I have seen this post : https://www.telerik.com/forums/error-script-controls-may-not-be-registered-before-prerender
But it seems i can't solve the problem...
I have to integrate TELERIK AJAX composant in an old project (Visual Studio 2010 / ASP.Net )
I understood that RadScriptManagerraise an error : Script controls may not be registered before PreRender
But i don't understand what i have to do.