It sounds like your system uses udev & hal to create the device and automount. Try restarting the hal and dbus daemons. That has helped me when a usb pendrive wouldn't automount.
However, your message states that you are trying to mount a camera, but what you posted is from connecting an external dvd drive. Or maybe I am seeing the messages for two devices. Try monitoring the messages when you plug the camera in.
In a shell enter "sudo tail -f /var/log/messages" and then plug in the device.
I just had a problem with an external usb drive. It wouldn't get assigned a device. Looking in /var/log/messages, it indicated that it was being detected but there was a usb problem.
Code:
May 23 08:25:42 hpamd64 kernel: usb 3-1: new high speed USB device using ehci_hcd and address 11
May 23 08:25:42 hpamd64 kernel: hub 3-0:1.0: Cannot enable port 1. Maybe the USB cable is bad?
May 23 08:25:42 hpamd64 kernel: usb 3-1: new high speed USB device using ehci_hcd and address 12
May 23 08:25:43 hpamd64 kernel: hub 3-0:1.0: Cannot enable port 1. Maybe the USB cable is bad?
May 23 08:25:43 hpamd64 kernel: usb 3-1: new high speed USB device using ehci_hcd and address 13
May 23 08:25:44 hpamd64 sudo: jschiwal : TTY=pts/1 ; PWD=/home/jschiwal ; USER=root ; COMMAND=/usr/bin/tail /var/log/messages
May 23 08:25:44 hpamd64 kernel: usb 3-1: device not accepting address 13, error -71
May 23 08:25:44 hpamd64 kernel: usb 3-1: new high speed USB device using ehci_hcd and address 14
May 23 08:25:44 hpamd64 kernel: usb 3-1: device not accepting address 14, error -71
Restarting the dbus and hal daemons didn't help. Next I tried: "sudo /sbin/modprobe -r ehci_hcd" and then "sudo /sbin/modprobe ehci_hcd" to unload and reload the ehci_hcd kernel module. This worked.