Array Utility error while building project

So, hmmm, strange problem here: I have a simple script which uses ArrayUtility… I press play and everything is cool, but when I press build I get this debug message:

Assets/Scripts/Other/RaceSequencer.js(141,30): BCE0005: Unknown identifier: ‘ArrayUtility’.

WHYYYY :<

What is ArrayUtility?: http://unity3d.com/support/documentation/ScriptReference/ArrayUtility.html

ArrayUtility is an Editor class, it is not available in builds. Make sure this RaceSequencer.js does not use this class when building, for example by using Platform Dependent Compilation