OS X startup disk has no more space available for application memory

OS X startup disk has no more space available for application memory

I am running a Simulation that is on purpose using a lot of memory.
Infact, more than available RAM and so the program should use swap space.
However, after 60 GB of Swap space are used, I get the following complaint
by my OS X 10.8.4: "OS X startup disk has no more space available for
application memory"
At this stage the RAM is fully used and Virtual memory is used up to ˜60
GB as well as the Swap is around 60 GB used in the activity monitor.
I tried this program on two different Macs with the same outcome and the
same critical amount of Swap where everything goes wrong.
My machine: MacPro, 2*Quadcore 2.7 GHz, 32GB RAM, free Hard-Disk space 1.3 TB
I checked my handcoded c++ program for leaks using Xcode and I understand
where the RAM usage is coming from.
I would be glad if anybody has a suggestion what the root of my problem is.
Cheers!