/usr/lib/dbus-1.0/dbus-daemon-launch-helper not executable by other

After an upgrade from Ubuntu 11.10 to 12.04, pulseaudio didn't work, and the root cause turned out to be that /usr/lib/dbus-1.0/dbus-daemon-launch-helper did not have o+x permissions. See this:

-rwsr-xr-- 1 root messagebus 292944 Feb 22 03:48 /usr/lib/dbus-1.0/dbus-daemon-launch-helper

and then when I did
sudo chmod o+x /usr/lib/dbus-1.0/dbus-daemon-launch-helper
pulseaudio worked.

As an additional clue, when I started the pulse audio volume control, it said that /usr/lib/dbus-1.0/dbus-daemon-launch-helper failed, and then when I tried running pulseaudio from the command line, it saud that dbus-daemon-launch-helper didn't have permissions to execute.

This is either an installer problem or a dbus problem.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: dbus 1.4.18-1ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic x86_64
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
Date: Mon Apr 30 23:18:00 2012
ExecutablePath: /bin/dbus-daemon
InstallationMedia: Xubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427)
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
SourcePackage: dbus
UpgradeStatus: Upgraded to precise on 2012-04-28 (2 days ago)