[EventCalendar] WP 2.2.3 seems to have broken EC??

[claire circuit]

I upgraded to WP 2.2.3 last night, and now my calendar doesn't seem to
be working properly.

Any links which are generated by actual calendar dates, e.g.
http://www.copsandrobbers.net/?m=20080321&cat=2 , just direct the user
to http://www.copsandrobbers.net/category/events/

This is bringing up a year-old blog post, and not the event on the calendar.

Clicking on other links (i.e. ones with post slugs) still works OK.

Can anyone shed any light on this?

I also installed the PodPress plugin, but have disabled it since and
this did not fix the problem.

Claire