I get a strange error message when trying to view the agenda for the current
day/week with C-c a a :

org-agenda-highlight-todo: Args out of range: #("  diary:      " 0 14
(org-category "diary" tags nil org-highest-priority 65 org-lowest-priority
67 time-of-day nil ...)), 26, 30

I can make it go away by deleting the following from the end of one of my
agenda files, or changing the date + or - one day.

** <2011-04-19 Tue>

Why would this break the agenda view?

Nik