System.Data.OracleClient requires Oracle client software version 8.1.7 or greater

It's a security issue, so-to-fix it simply do the following:

Go to the Oracle folder.
1-right Click on the folder.
2-on Security Tab, Add "Authenticated Users" and give this account Read & Execute permission.
3-apply This security for all folders, subfolders and Files (IMPORTANT).
4-don ' t forget to REBOOT your; If you forgot to does this you'll still face the same problem unless your restart your machine.

Application Run Environment

Operating system: WINDOWS2008 Enterprise Edition 64-bit operating system

Data server: oracle11g 32-bit

Web server: IIS7

Development environment:. NET 3.5SP1 System.Data.OracleClient

1. Log in with the administrator's user;
2, Find Dbhome_1 folder (my is C:\app\Administrator\product\11.2.0\dbhome_1), right click, select Properties-Security, in the group or user bar select "Authenticated Users", In the list of permissions below the "Read and run" permission to remove, then press the application; re-select the "Read and run" permission, click on the app; Select the "Advanced" button under the Permission box to confirm that "authenticated Users" is followed by "This folder, subfolders and files", Press OK to apply the change of permission to the folder;
3. Restart your computer for permission settings to take effect (please note that this step is important);
4. After logging in, run the ASP. NET application and get the data of Oracle database normally.

System.Data.OracleClient requires Oracle client software version 8.1.7 or greater