I seem to have the same or a similar issue. Tried several things posted in this thread, but unable to fix this.
# cat /root/.autoinstaller/microupdates.xml
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<patches>
<product id="plesk" version="12.0.18" installed-at="20140825T075459">
<patch version="40" timestamp="" installed-at="20150403T131430" />
</product>
</patches>
# ls -ld /dev/shm/
drwxrwxrwt 2 root root 60 Apr 3 13:28 /dev/shm/
# ls -la /dev/shm/
total 12
drwxrwxrwt 2 root root 60 Apr 3 13:28 .
drwxr-xr-x 8 root root 2120 Apr 3 07:20 ..
-rw-rw---- 1 root lock-manager 8388608 Apr 3 13:30 SharedLockManagerStorage_v2-a7bea213f1
# cat /etc/lock_manager.ini
[shm]
name=SharedLockManagerStorage_v2-a7bea213f1
# su -l psaadm -s /bin/sh -c 'id -Gn'
psaadm lock-manager swkey-data psaserv psasb
# su -l psaadm -s /bin/sh -c 'cat /etc/sw/keys/lock/repository'
# ls -ld /etc/sw /etc/sw/keys /etc/sw/keys/lock /etc/sw/keys/lock/repository
drwxr-xr-x 3 root root 4096 Jun 6 2014 /etc/sw
drwxrws--- 7 root swkey-data 4096 Apr 3 04:03 /etc/sw/keys
drwxrws--- 2 root swkey-data 4096 Apr 3 13:20 /etc/sw/keys/lock
-rw-rw---- 1 root swkey-data 0 Apr 3 13:20 /etc/sw/keys/lock/repository
# cat /etc/redhat-release
CentOS release 6.6 (Final)