Thanks to KSmiley for reporting this error and to Missy Moo for tracking it down!

Where a diary has multiple entries for one day AND the calendar was used to click on that day - the system should show all of those entries. Unfortunately a hangover from the days before multi-user existed in the code for 'viewByDate' and caused an Ooops.

This is now fixed.

KSmiley - if you're still seeing Ooopses in other areas if you could send me a screenshot when it happens I'll have a look further for you.