Cost increases in each iteration? My implementation of Multinomial Logistic regression

Hey guyz, I am trying to implement multinomail logistic regression using gradient descent, following http://ufldl.stanford.edu/wiki/index.php/Softmax_Regression

My data set has 7 ratings classes from 1 to 7. Cost in the cost function keeps increasing in each iteration, instead of reducing. Can any one help me with an extra pair of eyes?

My costFunction: http://pastebin.com/2FJcTkxy

calculatingPOfJ : http://pastebin.com/YNrB91K1