Walter
I am not sure what you are saying but if you remove the WARP does the page work correctly?
If you are starting a asynchronous postback when interacting with the grid, it would be equivalent to having the grid inside the WARP. If you can get the id of the button that triggers the postback, you could add it using the AddTriggerPostBack and then your redirect should work. But if there is some conditon that you check on the server, you may have to use the method described in the KB article above.
I do not think you can do a server.transfer or response.redirect in an asynchronous postback. Take a look at the following Knowledge Base article:
http://devcenter.infragistics.com/Support/KnowledgeBaseArticle.aspx?ArticleID=10040