Unhandled exception Telerik.Web.UI.WebResource.axd

1. Removing them solved it but I want animations.

2. I checked our code and fiddled around a bit. Ended up changing one line which solved my problem:
FROM:

var refreshNode = function (node) {
        node.collapse();
        node.get_treeView().trackChanges();
        node.get_nodes().clear();
        node.set_expandMode(Telerik.Web.UI.TreeNodeExpandMode.WebService);
        node.get_treeView().commitChanges();
        node.expand();
    }

TO:

var refreshNode = function (node) {
        node.get_nodes().clear();
        node.collapse();
        node.get_treeView().trackChanges();
        node.set_expandMode(Telerik.Web.UI.TreeNodeExpandMode.WebService);
        node.get_treeView().commitChanges();
        node.expand();
    }