ASP.NET XML Parsing Error: no element found Line Number 1, Column 1 Error

Question

Hey I found a weird temperamental page which randomly gives me the following error

XML Parsing Error: no element found
Location: http://kj2011/site_2011/nonprofit-database/overview.aspx
Line Number 1, Column 1:

This page was fine for like 2 weeks but as of yesterday I randomly get the above error. I was to delete the pages and recreate the error is gone but would come back again few hours later. I have some other templates

i.e http://kj2011/site_2011/nonprofit-database/financial.aspx

Which has the same Master File and User Controls but never gets the error just the overview.aspx page.

Any Ideas ?

Answer 1

In my case it was the AjaxControlToolkit.dll that was missing from the bin folder. Adding a breakpoint in the Application_Error method in global.asax as suggested above allowed me to find this out.

Answer 2

That sounds like the Firefox error page that's returned when FF expects HTML and gets an empty document instead. Try looking at it with Firebug enabled and see what the Net tab says - perhaps you have a good header, but no html.

Usually that kind of thing is not due to an ASP.NET error (since with those you still have a document body for the Yellow Screen of Death page), but is more along the lines of a networking error...

Would it be possible to try looking at it from another computer to see if that's the problem?