It's difficult to say, since you haven't provided the definition of vCompare2014-2013 (or vGreen or vRed for that matter). Are all of your variables being recognised as variables by Qlik, i.e. does the variable name appear in pink in the expression editor?
What does your expression evaluate to (what does it say at the bottom of expression editor)?
Depending on the definition of your variables (e.g. if they are values rather than expressions), it's possible that you should be referring to them without the $, e.g. vCompare2014-2013 instead of $(vCompare2014-2013)