The system error 10055: "An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full" occurs when an operation on a socket or pipe was not performed because the system lacked sufficient buffer space or because a queue was full. It indicates a shortage of resources on your system.
It can occur if you're trying to run too many applications (of any kind) simultaneously on your machine. It may also indicate you are not closing the applications properly. This is an issue with the operating system and not AB Tutor, if it persists please contact your support personnel or exit Windows and reboot your machine to remedy the problem.