If I understand the issue correctly, I believe the problem is with your javascript.
In your code you have the following line:
e.Row.Attributes.Add("onmouseover", "javascript:Tip('" + StopInformation + "', TITLE, 'Stop Information', TITLEFONTFACE, 'Verdana,sans-serif');");
Is TITLE suppose to be a variable or a static value? The javascript Tip() function currently thinks it's a javascript variable but it doesn't exist on the client. Can you post the JavaScript code you are using?