I'm experiencing the same thing here.
Actually, it just started AFTER I replaced a server, a SEPM server. I'll explain.
A while back I did an upgrade from 11.0.7 to 12.1 The first server, SEPM1 worked - it was an upgrade of SEPM over the 11.07 version. The SQL server lost network in the middle of upgrading SEPM2 to 12.1 so it crashed and burned - it acted so weird that I made a brand new server from scratch and did a native install of SEPM 12.1 to SEPM2 server.
So I was then running SEPM1 with an upgraded install to 12.1, and SEPM2 with a clean fresh install of SEPM 12.1 against our original SQL database that has been in use for years.
HOWEVER, strange things were going on with the communications, with the consoles, and with the alerting. Basically alerting was so screwed up, I had to turn off all email alerts and uncheck a bunch of logging. SEP itself was fine and seemed to be working.
SO, early this week, I took SEPM1 management services down, removed it from the SEPM structure in the console, renamed it in AD, and built a brand new server with a CLEAN fresh install of SEPM and SEP. So now both servers are fresh clean installs of SEPM, not upgrades, however the database is still the same one, and all the policies stayed in place - I did not change them or delete anything.
I needed to check for computers that didn't have SEP running on them so decided to use the clumsy push method - pretend I was going to push SEP out, and let it show me a list of computers..... but when I got to the final screen to search for computers, I get this error - ALL the time now. I'd never seen it prior to building a new server for SEPM1! Now since building a replacement server, I cannot push SEP out at all. Our push installs are broken totally.
Any clues??