Thanks for the replay Tom...

Although we have had the loss/corruption of index tags at the client, even after rebuilding them or restoring them we tend to get these same errors. That's why we think that its network connectivity. But what about this... are there any tricks to rebuilding the .cdx? I simple restore them from backup or if unavailable go back into the table and through the GUI add them back in. Maybe doing it all programatically would be better because the GUI might mess something up? Hmm....