This problem occurs when you have installed a 32-bit Devart driver together with a 32-bit OraClient on a 64-bit operating system.
All you need to do is;
Go to your iis settings. Go to your web site's application pool.Go to advanced settings of the application pool and set "Enable 32-Bit Applications" option to true.Save the settings, that is all.
Error Message: Can not obtain Oracle client information from registry. Make sure that Oracle Client Software is installed, or use Direct mode of connecting to server.
If there isn't any problem on the code side, then the reason can be about authentication and privileges settings. You need to adjust them as well.
Here is the solution:
You can reach my sample program from this link: http://www.nurhak-kaya.blogspot.com/2012/08/process-worker-web-service-exe-starter.html Run the Internet Information Services (IIS) Manager serviceGo to Application PoolsSelect the user DefaultAppPool and from Advanced Settings on the right side of the menu, change the Identity column as LocalSystem. This default user can be different in your working environment but for most of the developers this is going to be the user.
Right click on DefaultWebSite (or here can be different according to your project name), choose Add Application and after setting the allias and path, click on Connect As button. Choose Specific user option and then Set the credentials for your application. This user must have rights to run this service on IIS. For your local machine, these can be: Your…
Go to registry editor.Go to Computer\HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\11.0\TeamFoundation\Instances\xxx\Collections\XXXModify Offline DWORD value to 0.Start your Visual Studio Project again and select OK button to connect to TFS server.