First of all, Thank You.
I had to modify the following line (probably because I am using the 64 bit version):
BIN_PATH = $(ABS_PATH)/arduino-1.5.3/hardware/tools/sysroots/i586-pokysdk-linux/usr/bin/i586-poky-linux-uclibc
BIN_PATH = $(ABS_PATH)/arduino-1.5.3/hardware/tools/sysroots/x86_64-pokysdk-linux/usr/bin/i586-poky-linux-uclibc/
Also, my port was "/dev/ttyACM0" (Ubuntu) instead of "/dev/ttyUSB0".
Load (make flash) worked perfectly! However, I miss an console serial monitor entry in the Makefile