Summarize and organize yourself:
1. Check the registry, Oracle_Home under HKey_LocalMachineSoftwareOracle. If not, change it to correct;
2. uninstall ODP. net (or uninstall ODT. net, ODT contains ODP, ODT is. net is an integrated plug-in for connecting to and browsing oracle databases, and provides drag and drop operations on oracle databases, similar to. net for the resource manager of SQL Server );
3. If the ODT for. Net directory still exists, delete or rename the directory;
Restart the system and re-connect the ASP. Net program. If the same error persists, let's take a look. I suggest you reinstall Oracle.
Cause analysis: the system was originally installed with ORACLE 10G 10.1.0, and 10.2.0 was installed before it was restarted. As a result, the listener could not be started, but it still pointed to the location of 10.1.0, the listener cannot be started.
Processing Process:
1. Search for the Registry, point the listener to a new location, restart the service, and OK;
2. PL/SQL DEVELOPER cannot be connected. Other methods are normal. Uninstall ODP for. Net, which was originally installed on another logical disk, and reinstall it to the same location as ORACLE 10.2.0. When the system is restarted, the DEVELOPER still reports an error. However, the error message is blank.
3. After the DEVELOPER settings are changed, go to TOOLS> PREFERENCES... settings. In the CONNECTION under ORACLE, set oracle home and oci libiary to NULL for automatic detection. The connection is normal and the problem is solved.