Polling error sometimes (needs reboot)

We get the following error at the bottom of the scripttrigger log:

[ERROR] - Polling error...

With no evidence that it tried to run the script. The Polling error happens every time afterwards until Jenkins is restarted. I haven't seen any logs describing what the error is or why it's happening.

We've rebooted our server so that we can continue working. This problem is not reproducible. It has happened 3 times in the past 6 months (the last 2 times were within the last two weeks). When you're ready to work on it, we will keep the problem around when it happens again for debugging purposes.