Using plugin v0.4.4 on WP 3.5.2.
I set the date format for WP to US-typical mm/dd/yyyy. Your plugin ignores this and demands I type the dates in as yyyy/mm/dd which somehow my fingers don't want to type. (It also displays them that way on the events entry page.) Unfortunately, it won't accept yyyymmdd which would be fine by me. (It gives this error when I try: Warning: array_push() [function.array-push]: First argument should be an array in /home/content/83/7532983/html/wp-content/plugins/event-list/includes/db.php on line 375.)
Note that ISO 8601 wants us geeks to use either yyyy-mm-dd or yyyymmdd. Dashes optional, no slashes.
I looked at your code and saw that you have stuff in there for parsing dates... maybe the format just is getting lost somewhere.