"Parser error" in my "Global.asax" file

I am getting a "Parser error" in my "Global.asax" file:
<%@ Application Codebehind="Global.asax.vb" Inherits="Astronomy.Global_asax" Language="vb" %> Both "Global.asax" and "Global.asax.vb" exist and were function before this batch of updates were installed.
Global.asax.vb file:
Imports System.Web.SessionState Public Class Global_asax Inherits System.Web.HttpApplication Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs) ' Fires when the application is started End Sub Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs) ' Fires when the session is started End Sub Sub Application_BeginRequest(ByVal sender As Object, ByVal e As EventArgs) ' Fires at the beginning of each req ...