Unable to make VPN connection with network-manager

Binary package hint: network-manager

I am running Xubuntu Edgy with

Whenever I try to start the VPN connection, I briefly get a little VPN lock icon and an animated "connecting" swoosh, but it then disappears. From the console I get the following:

/bin/sh: /usr/bin/esd: not found
** Message: <information> Activating VPN connection 'PomonaVPN'.

libnotify-Message: Unable to get session bus: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.

** (nm-applet:4695): CRITICAL **: dbus_g_proxy_connect_signal: assertion `DBUS_IS_G_PROXY (proxy)' failed

** (nm-applet:4695): CRITICAL **: dbus_g_proxy_connect_signal: assertion `DBUS_IS_G_PROXY (proxy)' failed

** (nm-applet:4695): CRITICAL **: dbus_g_proxy_call: assertion `DBUS_IS_G_PROXY (proxy)' failed

From /var/log/messages, I get:
Jan 11 19:28:24 Hobo-jim kernel: [17179838.044000] PPP generic driver version 2.4.2
Jan 11 19:28:24 Hobo-jim pppd[4624]: pppd 2.4.4 started by root, uid 0
Jan 11 19:28:24 Hobo-jim pppd[4624]: Using interface ppp0
Jan 11 19:28:24 Hobo-jim pppd[4624]: Connect: ppp0 <--> /dev/pts/0
Jan 11 19:28:25 Hobo-jim pppd[4624]: nm-pppd-plugin: CHAP check hook.
Jan 11 19:28:35 Hobo-jim pppd[4624]: Terminating on signal 15
Jan 11 19:28:35 Hobo-jim pppd[4624]: Child process /usr/sbin/pptp 134.173.72.2 --nolaunchpppd (pid 4625) terminated with signal 15
Jan 11 19:28:35 Hobo-jim pppd[4624]: Modem hangup
Jan 11 19:28:35 Hobo-jim pppd[4624]: Connection terminated.
Jan 11 19:28:35 Hobo-jim pppd[4624]: Exit.

I don't know what's going on here, but I looked up esd, and it has something to do with the sound system, so I don't understand why that should be involved in VPN at all. I am able to ping the VPN server I'm trying to connect to, so it doesn't seem like there should be a connection issue. Is anyone else having a similar issue? I didn't get very far googling error messages.