Hello Jacques Woolston,
I suppose your problems are connected with the integration of RadGrid and RadToolTipManager. When you use these two controls you should not enable the Ajax of the RadGrid (EnableAjax="true"). In case you want to ajaxify the requests, made by the grid, you have to place both controls in an UpdatePanel and set the UpdateMode of the panel to "Conditional". Please make sure that you are using the latest version of the Prometheus suite as well - namely RadControls_Prometheus_2007_1_626.
You can find additional information in our online documentation
. In case my assumptions are not correct, please open a new support thread and send us a simple running project with instructions, how to reproduce the problem.
the Telerik team