Howto: Building the espruino code

I have managed to to install Ubunto 10.4 LTS in the Oracle VM, and I have done the steps described in the beginning of this chain. However, when I try to build the project I get the following error message. I'm a newbie to Linux, CodeSourcery and using make so the cause may be quite simple ...

asko@asko-desktop:~/Espruino-master$ STM32FDISCOVERY=1 RELEASE=1 make
Traceback (most recent call last):
File "scripts/get_binary_name.py", line 40, in

print common.get_board_binary_name(board)

File "/home/asko/Espruino-master/scripts/common.py", line 247, in get_board_binary_name

return board.info["binary_name"].replace("%v", get_version());

File "/home/asko/Espruino-master/scripts/common.py", line 237, in get_version

return subprocess.check_output(["sed", "-ne", "s/^.*JS_VERSION.*\"\(.*\)\"/\\1/p", jsutils]).strip()

AttributeError: 'module' object has no attribute 'check_output'
Makefile:300: *** Unable to work out binary name (PROJ_NAME). Stop.