I searched and found nothing for this problem. Here is the situation:

2 Squeeze machines
Sharing Public ticked
ping to each other ok
both show up in Network
machine A is able to transfer files to B
machine B when A is clicked in Network:

Unable to mount location

DBus error org.freedesktop.DBus.Error.NoReply: Message
did not receive a reply (timeout by message bus)

This window pops up immediately, as if there is no attempt to connect.

Any pointers would be appreciated.