Let's say you are getting this error when attempting to view your default.aspx page in a browser. In Visual Studio, when looking at the code of the default.aspx page, notice the line MasterPageFile="~/example.Master".

<%@ 
Page Title="" 
Language="vb" 
AutoEventWireup="false" 
MasterPageFile="~/example.Master" 
CodeBehind="default.aspx.vb" 
Inherits="example._default" 
%>

Sometimes, changing the ~ (tilde) to a . (period) will resolve this error.

<%@ 
Page Title="" 
Language="vb" 
AutoEventWireup="false" 
MasterPageFile="./example.Master" 
CodeBehind="default.aspx.vb" 
Inherits="example._default" 
%>