Network Printer Unavailable After Installing NIS 2015

My three machines (two Win7, one WinXP, all fully WinUpdated) just upgraded themselves from NIS 2014 to version 22.5.2.15.  The network printer attached to one of the Win7 machines continues to work properly from the WinXP machine, but is no longer available on the other Win7 machine, where it is shown as Offline.

If I try to re-add the network printer on the second Win7 machine, I get a message that "Windows cannot connect to the printer.  The server print spooler service is not running.  Please restart the spooler on the server or restart the server machine."  This is not true, of course, because I can print directly on the print-server machine and through the network from the WinXP machine.

Adding the name of the Win7 machine that won't print to NIS Settings > Firewall > General > Device Trust on the Win7 print-server machine, which was suggested in an article on this site, has no effect (though, of course, this shouldn't be necessary).

The only other oddity--and this may be a red herring--is that upon booting or awakening, NIS on the two Win7 machines first informs me that "You are connected to a private network," and then, a few seconds later, that "You are connected to a public network."  The network is shown as Private on both machines in Settings > Firewall > General > Network Trust.

So, to reiterate: I was able to access a printer attached to one machine from both of my other machines prior to the NIS 2015 upgrade, but afterwards, one of those other machines was no longer able to print..

Thanks in advance for any help.