After updating to the most recent version of WordBooker, Ai1EC started failing with errors logged:
Completely disable Wordbooker in Settings allows the Ai1EC to process.
Re-enabling WordBooker allows the WB's functions to work just fine without disabling Ai1.
I'm actually quite fine with manually turning it on and off since I personally add all events or trigger WB postings to Facebook, but this would be a problem for admins with more normal usage.
1. I'm not asserting that the conflict is a Wordbooker bug, nor am I asserting it's an All-inOne Event Calendar bug.
I'm just providing information that with the previous version of Wordbooker this problem did not exist.
2. I am not using the most current version of Ai1, but version 1.5. The issue may go away with the newest Calendar code, v1.7. I won't know because I'm not updating the calendar plugin due to the newer version's non-standard directory implementation and the donation of shell script file to my WordPress install. I'm not alone in this, so it may or may not be an issue Wordbooker wants to look at.