The problem is it does not work under strict and it is probably not doing what you think (it uses a global $sum and lexical $sum at the same time which is confusing).
لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
Comment on Re: Answer: How can I add all the numbers in an array with out doing a foreach loop?