Problem solved.
For anyone having the same issue: The Problem for the motorola MC40 is that the Vendor ID number is not the same as the Motorola vendor Id number (22b8). The MC40 vendor ID is "05e0". That was the root of the problem. So when following the instructions here make sure to enter the ID mentioned heretofore. Also not only do you have to add the id to the "51-android.rules" file in this format ("SUBSYSTEM=="usb", ATTR{idVendor}=="05e0", MODE="0666", OWNER="[user_name]"), but you also have to add the HEX version of the ID (0x5e0) to the "adb_usb.ini" file in .android directory: ~/.android/.