I am running iCal Version 5.0.3 (1605.4) on a Macbook Pro with Mac OS X Version 10.7.5.
Whenever I try to add a new event I go to the Toolbar, choose FILE, NEW EVENT and it jumps me to the CREATE QUICK EVENT on the iCal toolbar.
When I try to add an event in here, in most cases it will NOT add anything to the calendar. I am following the format of time, date and description and have tested a few different methods of entering the details and 8 times out of 10 it will not accept the event.
Prior to this version, I used to double click on the day and the New Event box would pop up and I could enter the details and save the event.