This message means that TBB was unable to delete a thread-local key it used, i.e. that pthread_key_delete() call returned an error. The solution to throw an exception might be considered too harmful for the problem, but that's the way it is, for now. Note that destruction of the TLS key only happens when TBB shuts down completely, i.e. either when the process completes or the library is unloaded. The last scenario, unfortunately, is known to be a tough nut for us: we already fixed some bugs related to that, but I'm afraid some more may still lurk there.
I am experiencing this behaviour as well. The program works fine, but throws this error and abort in the end. The problem is I am trying to use my program in a script, and I want to access its exit code. Any workaround or fixes?