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

When Oracle runs on the NTFS partition, the ORACLE_HOME directory is invisible to some users who are not in the Administrator group, and the account used by the Asp.net application under Windows Server 2003 is netword service, therefore, you cannot create an oracle connection. You only need to reset the permissions of the ORACLE_HOME directory. The procedure is as follows:
1. Log on as an administrator;
2. Find the ORACLE_HOME folder (my name is c: \ oracle \ ora92), right-click it, select attribute-security, and select "Authenticated Users" in the group or user bar ", in the following permission list, remove the "read and run" permission, and then press the application. Re-select the "read and run" permission and click the application; select the "advanced" button under the permission box, confirm that the application following "Authenticated Users" is "this folder, subfolders, and files", and apply the permission changes to this folder according to OK;
3. restart the computer to make the permission settings take effect (this step is important );
4. log on and run the Asp.net application to obtain data from the Oracle database.

This is also applicable to oracle11g 64-bit Databases