I had totally forgotten I had posted this question and when googling for something else, happened to run across it again yesterday. Since it might help someone else I'll post what I eventually discovered was the two problems.
"The version of the RAP files is not the one expected by the language lab. Please check you have updated the version or your RAP files." This error was due to inadvertently forgetting to include the RAP version.php file in the root html folder with the rest of the RAP files, that need to be there.
The Red5 server is not accessible or not started: Permission denied (13). I eventually realized this was due to SELinux. With setenforce 0 the message changes to "The streaming server is running and available." With setenforce 1 you get the aforementioned error message, even though the Language Lab works just fine. Since I would rather have SELinux set to enforcing, I just ignore the error warning.