Greetings Wise Guys! (meant in the best possible sense!)
Thanks very much for the feedback+info.
Unfortunately the server is quite important so have to wait to schedule a
reboot. Instead another server, of identical hardware, running
2.6.18-194.11.1.el5.x86_64 (behind a few updates), became apcupsd
master with 0 problems.
The problem 2.6.18-194.11.4.el5.x86_64 server is now an apcupsd client
with 0 problems.
So for now we have at least what's wanted - both servers on UPS & config'd
to shutdown safely if need be.
kernel-2.6.18-194.17.1.el5.src.rpm is released so one day will update both
servers to that & see if apcupsd stays happy or not.
Grateful thanks to the apcupsd developers+maintainers - it's good software
& our servers appreciate it!
(had several powercuts last spring, thank goodness critical servers shut