For those of you where changing udev.rules did not have the desired result, read on....
I have a Canon Powershot A80 camera that worked perfectly in Fedora 7 with kernel 2.6.21-1.
However, after yum update, starting with kernel 18.104.22.168-10, I got the same connection-problems as poster.
Changing udev.rules did not have the desired result, but I found the solution here :
So the command I used (as root) was this:
/usr/lib/libgphoto2/print-camera-list udev-rules-0.98 group users mode 0660 > /etc/udev/rules.d/90-libgphoto2.rules
Note that where it says “users” you should substitute the name of the group your account belongs to.
(In Fedora, that might actually be the same name as your username, since it likes to create a group just for you.)
Now my Canon Powershot A80 camera works perfectly again, running Fedora 7 with kernel 22.214.171.124-34 !