I have installed ODAC (Oracle data Access Components 64 bit) odp.net 4. But unfortunately it does not work with IIs Express. IIS express documentation says it
Probably too late now, but IIS Express 7.5 is 32-bit and cannot host a 64-bit process. I'm assuming that's what your problem is/was because I had a similar issue with the Oracle.DataAccess.dll. However, IIS Express 8.0 Beta can host your 64-bit site.
Visual Studio will only start the 32-bit IIS Express 8 process when you use it to start the site (F5 or Ctrl-F5). However, you can start the 64-bit process from the command line and then attach to the IIS Express process from Visual Studio, if you want to debug. The command I use is:
c:\Program Files\IIS Express\iisexpress.exe /site:SiteName
The the default IIS Express config file is in your documents folder at IISExpress\config\applicationhost.config
. That file contains the definitions for your sites and gives you the site name, which you can change.
Make sure you read the instructions for Upgrading from IIS Express 7.5.