internet calendars not letting me set reminders

I have my default calendar and can set reminders fine in that calendar.  However, I get the following message when trying to set a reminder...

"The reminder XXXX will not appear because the item is in a folder that doesn’t support reminders. Is this OK?"

My mail folders are all IMAP except one exchange folder, but the default is an IMAP.  i do not think the folder type does/should affect an internet calendar's ability to set reminders.

It's annoying that i cannot set reminders for ical events, and this must be something that can be fixed.

I appreciate any help in resolving this.