I would like to ping one vmware guest from another one. Both are Windows XP and use NAT. I set IP manually for VMnet8 to 192.168.18.1. (no using Obtain IP address automatically)
I know it is an old question, but I had a similar trouble recently. On VMware Workstation 12.+ go to Edit -> Virtual Network Editor...
Select a network used by the problematic VM and make sure that "Connect a host virtual adapter to this network"
checkbox is set for this network. In my case, it was not. After it was set, the host was able to ping the guest and guests were able to talk to each other.