In fact I finally cleared the hang state by rebooting. Unfortunately I don't have much in the way of error messages, etc., to use to track down the error. No error messages, just a long wait. When I realize that I'm seeing the wait I use ping to see if my worldy node can see the stalled node. Invariably I cannot ping at that point.
Ping just hangs waiting.
Other tools like PADE's pvmtidy utility tell me I have no route to that node. The strange thing to me is that I can always telnet to one of the still visible nodes and then telnet from it to the apparently hung node with no problems. I don't know if this is related to the lamboot problem. I have been limping along with this by just waiting it out when it happens and then continuing with my runs. I should probably get this nailed down before trusting that the lamboot problem really is one.