So primarily this error message already shows you that there is something happening with a scheduled event (SE). What you can do is check if there are any scheduled events kicking off.
Using Logs in SE
What might be a good thing to do to find the problem is adding a log to the start of every SE to state that the event is started and one to the end to state the event is finished. If in this case one errors out, you can see this because the event was never finished (missing LOG for finished SE).
Calculating interval time
Another great way to track which SE might error is by seeing the interval of the errors and checking which SE has the same interval for kicking of :)