I am having this same problem. I am running Fedora 12 and installed Calibre 0.6.51 from the Calibre website. I have an non-updated Sony 500. It is found if I run Caliibre from root, but not from my user account. In the terminal it repeats the following error:
Unable to open device <calibre.devices.prs500.driver.PRS500 object at 0x908d3ac>
Traceback (most recent call last):
File "/home/kovid/build/calibre/src/calibre/gui2/device.py", line 106, in do_connect
File "/home/kovid/build/calibre/src/calibre/devices/prs500/driver.py", line 255, in open
DeviceError: Unable to find SONY Reader. Is it connected?
Connect to device failed, retrying in 5 seconds...
I have added my user to plugdev, usb, and disk (I had to create plugdev and usb).
ls -l /dev/sd? returns:
brw-rw----. 1 root disk 8, 0 2010-05-01 01:41 /dev/sda
brw-rw----. 1 root disk 8, 16 2010-05-01 01:41 /dev/sdb
These are my two hard drives.
I have also tried ls -l /dev and the list is identical whether or not the Reader is plugged in.