When installing Symantec Data Loss Prevention (DLP) Enforce Server (Platform) after providing all of the installation information and clicking on the "install" button. You see a new window pop-up with the message "Error calling OCIErrorGet" with no other details.
You may see in the background that the install hung on the "Validating Oracle Configuration"...
Observed in 15.7, and 15.8 but potentially applicable to any version.
You can test the JAVA_HOME variable by opening a CMD window and using the "java -version" command. For DLP 15.8, this should show java version 8 build 262.
You can test the tnsnames.ora by using the "tnsping protect" command, where protect is your Oracle Service Name.