When backing up my Hyper-V VMs over the network. I was getting the following error message with one file that was 60GB in size:
Not enough server storage is available to process this command.
A quick Google search found several references, a number of which pointed to this. The current value on my (Windows Server 2003) file server was 18. After upping this to 21 and rebooting the server, the error disappeared and I could successfully copy my 60GB file over the network.
After running into this again with other files I had to increase to 24.