Load sencing

Hi, I've wrote a program for arduino. The program is for weight sorting job which is to be executed by arduino according to the variable input voltage.
The program I wrote can be found through this link.
This is for master arduino which will be receiving variable voltage from digital indicator and the indicator will receive input from loadcell.
The problem is when I try to compile this program and upload to arduino, I get red signs indicating something that I don't understand.
Could you tell me what is wrong with my arduino programing?
Another question is, should the arduino software be installed in the program file only?