I too have this issue too. A work around is enabling “Create events by single-click”.
Go to Plug-ins > Scheduler > Settings > General Settings header > Check “Create events by single-click”
Now you could click a day in the calendar to create your events. I do recommend the developer to fix the issue you refer to. This would be a great calendar if everything works.
In wordpress 3.0.4, the words and alignment is a little off (tested in I.E. and FireFox).
