A newly installed application exists with error whenever it is closed.
Environmental
Uninstall SQL Optmizer for Oracle, and delete the Optimizer data folder if it still exists after uninstall, e.g. C:\Documents and Settings\[login user]\Application Data\Quest Software\Quest SQL Optimizer for Oracle.
Ensure that there is no Optimizer registry value under both HKEY_LOCAL_MACHINE\SOFTWARE\Quest Software and HKEY_CURRENT_USER\Software\Quest Software after the uninstall.