You can view the issue at http://www.rcca.org.au/event-calendar/
I have tested this with latest builds of Safari 5, IE 9, Firefox 4 and Chrome 10.0 under Windows 7 SP1 and OSX 10.6.7.
Firefox 4 and IE 9 are rendering the calendar days wider than the actual calendar box. I changed the width variable and confirmed the background calendar box changes, yet the calendar days (being 7days wide) do not change.
Chrome and Safari 5 are not exhibiting this issue. The issue wasn't present on v1.0.3