Hi
mine is 2.6.35-22-generic.
which linux kernel version are you using?
As I know that 2.6.31 has the ttyACM bug ,if you open /dev/ttyACM0 ,you may get input/output error.
which linux kernel version you are using?
As I know ,the 2.6.31 has the ttyACM bug,it may cause input/output error when you open ttyACM device.