When connecting to database using Oracle Root, error message 'Cannot find OCI DLL in : <ORACLE_HOME_NAME>' is displayed. On checking the Homes_Editor by clicking on the List-of-values icon (...) all HOMES appear valid i.e no entries are in RED. Connecting using client other than root allows connection to database.
This may be due to the ORACLE_HOME_NAME indicated in the Root, which has been manually edited in the registry, having uppercase letters whereas the ORACLE_HOME_NAME in the client (which is meant to be identical) has lowercase, or vice,versa.
Modify Registry key entry:
1. Go to Start | Run and type in regedit.
2. Browse to HKEY_LOCAL_MACHINE | SOFTWARE | ORACLE
3. Copy the string value of the key ORACLE_HOME_NAME
4. Edit the value in key ORACLE_HOME_KEY so it matches the following: SOFTWARE\ORACLE\ KEY_oracle_home_name value.
ORACLE_HOME_NAME = OraDb10g_home1
ORACLE_HOME_KEY = SOFTWARE\ORACLE\ KEY_OraDb10g_home1
Disclaimer : Quest does not provide support for problems that arise from improper modification of the registry. The Windows registry contains information critical to your computer and applications. Make sure you back up the registry before modifying it. For more information on the Windows Registry Editor and how to back up and restore it, refer to Microsoft Article ID 256986 "Description of the Microsoft Windows registry": http://support.microsoft.com/default.aspx?kbid=256986