Description of problem: I have the thunderbird-lightning Add-On enabled and when thunderbird is first started the meeting reminders pop up but cannot be dismissed using either the "Dismiss", "Dismiss All" or "Snooze" buttons. The error console displays the following:

--- START ERROR TEXT---
Error: uncaught exception: [Exception... "'<error>' when calling method: [calICalendar::modifyItem]"  nsresult: "0x804a0002 (<unknown>)"  location: "JS frame :: file:///usr/lib64/thunderbird-2.0.0.18/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/components/calItemModule.js -> file:///usr/lib64/thunderbird-2.0.0.18/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/js/calAlarmService.js :: cas_snoozeAlarm :: line 230"  data: no]
--- END ERROR TEXT-----

Version-Release number of selected component (if applicable):
thunderbird.x86_64 version 2.0.0.18
thunderbird-lightning.x86_64 version 0.9


How reproducible: Always


Steps to Reproduce:
1. Start the Thunderbird mail client.
2. Create a meeting and enable the reminders.
3. When the alarm window pops up, try to clear it by pressing the Dismiss button.
  
Actual results: The meeting alarms are not cleared and will periodically keep appearing.


Expected results: The meeting alarms should be cleared.


Additional info: I tried un-installing and re-installing thunderbird-lightning unsuccessfully.