plank crashes when starting "Unable to watch the launchers directory"

[Simon Butcher]

$ plank
[INFO 11:11:25.001326] [AbstractMain:176] Plank version: 0.2.0.738
[INFO 11:11:25.001389] [AbstractMain:177] Kernel version: 3.2.0-36-generic
[INFO 11:11:25.001428] [AbstractMain:178] GLib version: 2.32.3
[INFO 11:11:25.001461] [AbstractMain:179] GTK version: 3.4.2
[INFO 11:11:25.001493] [AbstractMain:180] Wnck version: 3.4.0
[INFO 11:11:25.001531] [AbstractMain:181] Cairo version: 1.10.2
[INFO 11:11:25.001569] [AbstractMain:182] Pango version: 1.30.0
[WARN 11:11:25.300400] [DockItems:93] Unable to watch the launchers directory. (Unable to find default local directory monitor type)
Trace/breakpoint trap (core dumped)

ProblemType: Bug
DistroRelease: elementary OS 0.2
Package: plank 0.2.0~bzr738-0elementary1~precise1 [origin: LP-PPA-elementary-os-daily]
ProcVersionSignature: Ubuntu 3.2.0-36.57-generic 3.2.35
Uname: Linux 3.2.0-36-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.1+elementary3~precise1
Architecture: amd64
CrashDB: plank
Date: Tue Jan 29 11:14:17 2013
InstallationMedia: elementary OS 0.2 "Luna" - Daily amd64 (20121231)
MarkForUpload: True
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: plank
SuspiciousXErrors.txt:

ThirdParty: True
UpgradeStatus: No upgrade log present (probably fresh install)