That is what it is shown to me when I use ajax.net with asp.net 2.0. It was a weird error..as it works perfectly fine in Firefox. After meddling for several hours, I remember Triplez words
"Never use vs 2005 build in server for ajax"
A quick switch to iis solved the problem..so..if you are working with ajax in vs 2005..sticks to IIS. Vs 2005 buildin server dun work well with ajax.