After installing Billing, sw-cp-server intermittently silently stops / crashes

[Magnafix]

Since I installed the Plesk Billing module, now Plesk goes away after a few minutes of clicking around configuring it. I have not figured out if it's a specific action which causes the shutdown, and the associated log doesn't seem to say much:

2013-04-05 12:42:27: (server.c.1543) server stopped by UID = 500 PID = 13460

It's not a resource issue as far as I can tell.

# df -hl
Filesystem            Size  Used Avail Use% Mounted on
/dev/vzfs              96G   20G   77G  21% /
/dev/simfs             96G   20G   77G  21% /tmp
/dev/simfs             96G   20G   77G  21% /var/tmp
none                  3.0G  4.0K  3.0G   1% /dev
/dev/vzfs              96G   20G   77G  21% /var/named/run-root/var/run/dbus


# free -m
             total       used       free     shared    buffers     cached
Mem:          6031       1225       4806          0          0          0
-/+ buffers/cache:       1225       4806
Swap:            0          0          0

I already tried bootstrapper repair.

(

# /usr/local/psa/bootstrapper/pp11.0.9-bootstrapper/bootstrapper.sh repair
. . .

                             Congratulations!
        All stages of the upgrade were successful.
        psa is now running on your system.

)


Here are some system version details:

MediaTemple dv4
CentOS release 5.9 (Final)
Linux obfuscatedservername.com 2.6.18-028stab101.1
psa-libpam-plesk-11.0.9-cos5.build110120608.16
log4cpp-plesk-0.3.5rc2-10.12051715
psa-pylibplesk-11.0.9-cos5.build110120608.16
plesk-billing-plugins-11.0.9-cos5.build110120606.19
plesk-billing-11.0.9-20120606.04
plesk-core-11.0.9-cos5.build110120608.16
plesk-base-11.0.9-cos5.build110120608.16
plesk-mail-qc-driver-11.0.9-cos5.build110120608.16
plesk-skins-11.0.8-12051419
plesk-l10n-11.0.9-cos5.build110120827.16
sw-sso-2.12-12053113

Any ideas?