Frame Recognizers are called in the data collection thread. This means that there is no way to abort if a Frame Recognizer runs into a serious error, because then data collection would stop. If a Frame Recognizer runs into a problem so serious that it cannot continue its work, it must figure out something to do. In such a situation, it is acceptable for it to put itself into a state where it always returns eContinue.
A Frame Recognizer may throw a CfdFrameException exception in its EVENT_HANDLER code. This is the only case allowed; a Frame Recognizer should not generate an exception in any other circumstance.