Yeah, this was the problem in the end. A pop-up window VI, wasn't popping up and as a consequence, an associated VI was timing out and communicating this error. Thanks for helping steer me to the solution, everyone. Much appreciated.
There was nothing on the error list, but the error simply seemed to be a time-out error that occurred because a popup window that prompted the user to press a button wasn't launching, thus leading to the time-out. Thanks for your suggestions.
