Custom Error page - with active Error message

Hope this can be done. if possible I prefer VB.
I have create a custom error page and it is working fine. what I would like to do is to add a label to it the will pickup the subject error message and display it on the custom page I created. for example 

I want to be able to take only the "The resource cannot be found" and add it to my custom page, which has only one label that can change upon the original message displayed.
Thanks