Linux Mint 17.3 || Arduino IDE 1.6.5 || avrdude: ser_open(): can't open device "

Hey guys.

I hope you can help me.

Thats my error when i dont use root:

avrdude: ser_open(): can't open device "/dev/ttyACM0": Permission denied

Thats my error if i use root:

avrdude: ser_open(): can't set attributes for device "/dev/ttyACM0": Inappropriate ioctl for device
ioctl("TIOCMGET"): Bad file descriptor

I added myself into the dialout group but it doesnt work. Additionally this line dont looks normal.

lrwxrwxrwx 1 root root 5 Aug 12 13:43 /dev/ttyACM0 -> loop0

In other topics i looked for their is only one root and then their is dialout.

Hope you guys can help me.

THanks for trying.

Pietus3