TCLVM-04-ad8353bc.vswp is for swapping guest memory (in your case, 64MB). If you don't have a memory reservation for the guest, you need sufficient space on the datastore to swap out all of guest memory, or the VM won't power on.
vmx-TCLVM-04-2911065020-1.vswp is for swapping the VMX process. This allows you to swap much of the 119MB overhead. Based on the fact that you can only start 38 VMs, I suspect that you may not have this file for every VM that is powered on. If there isn't space for this swap file, then the VMX reservation has to come from physical memory.