Connecting to an Oracle 8i database and then browsing the data in the schema browser for tables that contain UDT's causes TOAD to display an OCI-22303 error message.
This is an Oracle Call Interface error and is normally caused because the Oracle client you are using is pre 8i. Check the following to ensure that you are using the 8i client (oraclient8.dll) or greater, if you do not have an 8i or greater client installed you will need to install it, if you do then check the following:
To configure this correctly please check the following:
1. Configure the Oracle registry to use the correct home.
Check your registry via Start| Run, type in Regedit, and look under HKEY_LOCAL_MACHINE, SOFTWARE, ORACLE, ALL_HOMES: What is the HOME_COUNTER value? If it is more than 1 you will have multiple Oracle homes such as ID0, ID1, ID2, etc up to the HOME_COUNTER value minus one. Simply ensure the LAST_HOME value is the correct ID value which points to the path to your current Oracle_Home. In other words, if ID1 has a path to your C:\Orawin95 on your machine, then you want LAST_HOME to have the value 1 since Toad looks to LAST_HOME for the Oracle application extensions.
2. Check that TOAD is utilising the correct oracle dll.
Open Windows Explorer
Drill down to %ORACLE_HOME%\Bin
Search for ORA*.dll under the Bin directory
For 8i the dll in the bin directory should be oraclient8.dll, (9i will be oraclient9.dll). make sure it is in the bin directory. If the search returns multiple dll`s then rename the old dll`s to olld. For example, pre 8i dll's were Ora803.dll ,804.dll ,805.dll rename them to Ora803.old ,804.old ,805.old this will then ensure TOAD uses the 8i dll.
3. Check that your environment path has the %ORACLE_HOME%\bin directory at the very start of the statement. For example:
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