This didn't break the plug-in but there were a few issues with the code that I had to go in and fix because I kept getting flags/errors on my admin page... the two things that I found were:
1) in the file events_install.inc.php on line 4, there were extra spaces around the 255 in the line "VARCHAR(#255#) NULL". I removed the spaces and the error went away. (in this example I have placed a # where the spaces were.)
2) in the file er_add_event_form.php on line 412.. the same thing happened. There were extra spaces in the line: $checked = in_array(#$category_id, $event_category#); I removed the spaces and the error went away. (in this example I have placed a # where the spaces were.)
Like I said, this did not break anything or cause any problems other than the error flags I received. I just thought I should point it out so that someone can go in and fix it for the next version.