Admins responded fairly quickly to my inquiry and got things running again.  I'm now getting speeds ranging from 300 or so pps on really old hardware (an Athlon 64 3700+ and a 2.8-GHz Pentium 4, with the Athlon 64 tending to run a little bit faster) to about 2500 pps on a VPS with eight Xeon E5-2670 cores. A Core 2 Quad Q6600 is good for about 1500 pps.  The pool has found four blocks in the past two days (plus two orphans), but nothing since I started mining there.  We'll see what happens overnight. I was getting nowhere fast with solo mining.