I have a 2010 Mac Pro with 12 core (2 x 2.66) with 64 gigs of ram. I've never run of memory before.
I only seem to get this message when trying to start Calendar for some reason. It never actually starts now.. it merely never opens, followed by that message.
Not sure if what the issue is. I googled for it but was unable to find anything on it, most likely given the age of OS X Mavericks 10.9 DP1