Fedora (13 and 14) cannot connect to arduino mega 2560

I am trying to program an Arduino Mega on my fedora 14 (same behavior on two other fedora 13 systems) system so far both version 22 (I am using this one due to rxtx in the packaged one not supporting the new usb serial chip) will hang for about a minute when I click the tools menu and the Arduino is plugged in. When the mega is not plugged in it works at full speed. Also a Duemilinove works fine on all three systems.

After I finally get it up most of the time it won’t show /dev/ttyACM0. When it finally does show it and I get it selected and hit the upload button it sits there for the longest time and then either gives me the error ‘/dev/ttyACM0 not found’ or complains about a lock file existing on /dev/ttyACM0. When it complains about the lock file I open it up and the process ID is for the only instance of the Arduino software that is running. Ocasionally it will work on smaller sketches like the blink sketch but it is so unreliable that there is no way I can effectively program it.

After booting the machine up doing a lsof on /dev/ttyACM0 lists nothing. My permissions for /dev/lock and the device are set correctly, also my user is in all the appropriate groups. Also I have tried all of the above on both root and my user account.

Any suggestions on how to fix this or where to even begin to debug it would be greatly appreciated.

You might need to upgrade the firmware on the 8U2 that's acting as a USB-serial bridge: http://arduino.cc/en/Hacking/DFUProgramming8U2