First of all, thank you for creating this plug-in. Exactly what we needed.
I noticed there's a bug when you use the [Event_Registration_Calendar] code for the calendar. I have permalink enable and the issue is when you click the calendar forward and backward buttons to navigate to the different months, I get a page not found error. As soon as I disabled permalinks, it's working fine. Wondering if you can shed some light into this issue - we'd like to continue to use permalinks if we can - it's just better practice!