That's really odd indeed. Let me recap
- you are using for the Mac 10.255.255.1 and the PC 10.255.255.2
- the network is a gigabit network
- your Mac can ping the PC and vice versa
- each computer can mount the shares/exports from the other machine
- there's no firewall which might block incoming/outgoing connections
- VEP neither 'sees' the other machine nor can it connect via given IP address, even after a reboot
Have you checked http://community.vsl.co.at/forums/p/29058/187656.aspx ? I am running out of ideas...
/ewo