We are also experiencing out of memory errors with the virtual machines. We are running four simultaneously on a 8 core box, with 8GB of ram, with each virtual set to use 1GB of ram.

Q: We are also experiencing out of memory errors with the virtual machines. We are running four simultaneously on a 8 core box, with 8GB of ram, with each virtual set to use 1GB of ram.
A: limit the number of mailboxes you are updating at one time and ensure you are running V2 since the memory leak issues should have been resolved.