asp.net mvc - Why are users taken to /?aspxerrorpath=/UrlRouting.axd -

I was just looking at analytics for the ASP.NET MVC 1 site running on mono.

I found that once the users are brought to this URL: /? Aspxerrorpath = / UrlRouting.axd

What will be the reason?

An error?

  /  

Your error handler

  / url routing.axd  

The exception was thrown.

See your CustomAmerts section in web.config