Same problem here. Trying to set Open File alarms is incredibly buggy, and even if you do successfully set one, and even if it does happen to work once or twice on a repeating event, don't trust it, because the joy won't continue. I used to run my life by iCal, but since upgrading to Mavericks, it's been nothing but grief and aggravation. I'd like to migrate to Google, but, hello? Privacy issues.
If I'd known that a free "upgrade" was going to break something so fundamental as a formerly useful calendar, I'd have give that particular freebie a pass.
And while we're on the topic of inadvertantly having downgraded our applications, Apple, take note: you should not helpfully make our alert notifications disappear after a nanosecond. Additionally, you should hasten to allow US the ability to decide how long to snooze an event, or even reschedule an event from within the alert window. A generic and unmanageable "Snooze" for an alert is just annoying. (I missed the snoozed alert for "Plug Grandma's life support back in," while I was in the bathroom and you can imagine the consequences. Okay, not really, but just sayin' -- get your effing house in order and make sure you don't break important basic apps with upgrades. Oh, and also, please FIX THIS!)