adding new events

When I open Sunbird portable (calendar) and add a new event it is visible for numerous minutes...I can sign out then back in and it will still be visible...then after a while it disappears and I cannot locate or view my documentation.

I didn't dismiss or do anything to the event I added, e.g. birthday date of someone, etc.

Any idea's....

version info:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8a5) Gecko/20050203 Mozilla Sunbird/0.2

Thanks in advance,