The comments on Harish's blog entry from two years ago give a lot of different solutions to the 'Could not load type "Global" ' problem that you sometimes get in ASP.Net. My solution to the issue was an interesting twist on one of those answers.
I had recently upgraded an application from ASP.Net 1.1 to ASP.NET 2.0, but to keep supporting old versions of the application, I branched it off in Subversion. To make sure the old version still worked, I checked out the old code into a new folder, then I went into IIS and simply moved the location of some virtual directories to point to the old code. It all worked and forgot about it.
Until later, when I came back to make some changes to the new application, started it up and got the message:
Parser Error Message: Could not load type 'WebApplication1.Global'.Source Error: Line 1: <%@ Application Codebehind="Global.asax.cs" Inherits="'WebApplication1.Global'" %>
I couldn't make heads or tails of it, but a web search led me to Harish's post and lots of different answers, several of which I tried, but none of which worked. One suggestion was to make sure the application was set in IIS to use ASP.Net 2.0 rather than 1.1, and even to set it to 1.1, click Apply, set it to 2.0 again and click Apply, just to make sure it took. Another was to make sure the application was compiled. If there's no assembly built for the application, it won't load.
I checked the ASP version, and it was indeed set to 2.0; I said, "Duh!" to compiling, but made sure there was an assembly in the bin directory, and there was; so I was at a dead end.
But I'm sure by now you see where this is going. As I opened up IIS to check the ASP.Net version configuration again, I happened to glance down at the local path for the virtual directory on that tab. And what did I see? The directory was still pointing at the path to the branched directory; a perfectly legal application, but one that was built using ASP.Net 1.1, and also had been cleaned sometime in the not-too-distant past. So the version I had configured in IIS was neither compiled, nor a 2.0 application! No wonder the error came up.
So I have an additional solution for this problem. Check your virtual directory location and make sure it's pointing to the application you're expecting it to be.