Issues loading 'latest' firmware (Servotor32)

Hi all -

I have seen a few similar issues on teh forum but none of the solutions have worked. I apologize in advance if I have missed something -

While trying to flash the Servotor, and following directions for the Sparki, as noted in other posts, This is the error message I get:

Arduino: 1.6.0 (Linux), Board: “Arduino Leonardo”

Sketch uses 10,350 bytes (36%) of program storage space. Maximum is 28,672 bytes.
Global variables use 923 bytes (36%) of dynamic memory, leaving 1,637 bytes for local variables. Maximum is 2,560 bytes.
avrdude: ser_open(): can’t open device “/dev/ttyACM0”: Device or resource busy
avrdude: ser_send(): write error: Bad file descriptor
Problem uploading to board. See arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

Any ideas what might be causing it? As a test I was able to load the code into an off-th-shelf Leonardo with no problem. That would seem to indicate the PC is not the prob;em. I am running Linux Mint 17.1. This is a new construction and I have run into a few problems with PoMoCo as well. I am still trying to work through those though.

Thanks!