I also use DHCP
Problem of stability solved.
It was the butler what done it!<G>
Drive where catalog was kept was in a dock connected to USB port in the old (2006) mini. Somehow it wasn't seated properly, and repeated efforts to reseat it didn't work, a fact noted after other network related things were screwy as well. Pulled that drive and put in another for the mini's use, re-established catalog. All is well, no issues at all after several days.
The "pulled" drive is happily working away, reliably, in a similar dock connected to a win7box.