natural logarithm: argent Help from every one ?

 
I need your argent help, I want some one tell me how can I write natural logarithm or Log in my equaiton inside meta4 editor program? it gives me always undefined function best regards,
 
the function is MathLog(x) where x>0. All matemetical functions start with Math...
 

thanx allot and I really appricated your help. it seems works fine with me.