This message might appear in "Citrix Presentation Server 4" as well. I solved this problem by enabling NetBios on the network card for each server where the zone was defined (each Server in my Farm has 3 network cards/ports).
See the link to "Citrix Support Document ID: CTX101877
" for information about this event.
I came across this problem when a Windows 2000 site had driver teaming configured in load-balanced mode instead of stand-by failover mode. When using driver teaming, browse lists are contaminated because there is more than one MAC address per IP address. This is why the Citrix server could not locate the data store.
From the Citrix KB: "This is normal. When the server with the DS is rebooting the other server cannot talk to the data store. When this happens an event is placed in the event log so that administrators are made aware that the serve can not contact the data store".