Could not load file or assembly 'X' or one of its dependencies.

You're seeing this Configuration Eror:



And you're using IIS7 with ASP.NET and using 32-bit applications.

Chances are, you just installed a fresh copy of IIS and you haven't changed around any defaults.

You're in luck because the fix is easy.  Here's what's going on.

The default installation of IIS 7 is to disable 32-bit Applications.  Afterall, IIS 7 comes with Server 2008 and Server 2008 is an x64 system.

So all you have to do to get rid of this error is to Enable 32-bit Applications in IIS.  Here are the steps:

1. Go to Start and type in inetmgr to launch IIS
2. In the left page, select Application Pools
3. In the middle pane, select the application pool corresponding to the web-application that is giving you this error.
4. In the right pane, select Advanced Settings:
    
5. This is what you'll see: Enable 32-bit Applications is set to False.
   
6. Go ahead and set that to True:
   
7.  Click OK

And you're super awesome application that depends on 32-bit DLLs is back in business: