No, I never did get an answer.
As to your issue, I have seen intermittent network connectivity like that
when there are two NICs (network cards) on a server that are teamed. Virtual
Server seems to have a problem when using the team for a guest. If you do
have teamed NICs, bind one of the individual NICs to the guest instead of the
team. (Note, it doesn't matter if the individual NICs have TCP/IP active on
them. They just need Virtual Machine Network Services bound to them.)
I've also seen certain network and teaming drivers
cause this issue.
Usually, updating to the latest version helps but I had to go back to an
older version once.