If you are migrating RadGrid from the "Classic" controls to RadGrid for ASP.NET AJAX I would recommend following the instructions listed in this article
. It lists the modifications that need to be made to successfully migrate RadGrid.
The error with the layout of the grid could be caused by the Browser Link feature in Visual Studio 2013. There is a post here
that describes some of the errors that could be caused by it. In order to avoid the issues try disabling the Browser Link as described in this article
Also make sure that you are using the latest version of our controls (currently 2014.1.403). It could be downloaded from our site after logging in with your credentials.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.