My whole idea on how to make a jumping function is broken any ideas/advise?

Check this code out and see what you can figure out. function love.load() love.graphics.setBackgroundColor( 255, 255, 255 ) am2 = 100 am = 100 xam1 = 100 xam2 = 100 charecter = {400,550,100} speed = 100 end function love.draw() love.graphics.setColor(255,0,0,255) love.graphics.rectangle("fill&q...

Attempt to perform arithmetic on global. What does this mean?