Hello guys and ladies

How do i fix for Drive C: If Adobe AIr detects to default drive C:\ or Installed Windows OS D:\ or E:\ ...

I have created code for FileUtils.as
Code:
package net.sourceskyboxer.flexos.command.utils
{
	import flash.filesystem.File;

	public class FileUtils
	{
		private static var _drive:File
		private static var _drives:Array;
		
		private static const DRIVE_C:String = "C:";
		private static const DRIVE_D:String = "D:";
		private static const DRIVE_E:String = "E:";
		private static const DRIVE_F:String = "F:";
		private static const DRIVE_G:String = "G:";
		
		
		public static function get WindowsSystemDrive():File
		{
			_drives = File.getRootDirectories();
			var i:int = 0; i < _drives.length;
			if(_drives[i] == _drive.getDirectoryListing())
			{
				if(_drives[i].name == DRIVE_C)
				{
					_drive = _drives[i].esolvePath(DRIVE_C);
				}
			}
			return _drive;
		}
	}
}
And i try from code - but it does not work. Why do i not get C:\ If i have installed Windows in Drive C:\.

drive_C_Windows_installed.PNG

Adobe Air Application got error:
Code:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
	at net.sourceskyboxer.flexos.command.utils::FileUtils$/get WindowsSystemDrive()[C:\Users\Joe\Adobe Flash Builder 4.6\FlexOS Command\src\net\sourceskyboxer\flexos\command\utils\FileUtils.as:22]
	at fxCommand/onCreationCompleteHandler()[C:\Users\Joe\Adobe Flash Builder 4.6\FlexOS Command\src\fxCommand.mxml:27]
	at fxCommand/___fxCommand_WindowedApplication1_creationComplete()[C:\Users\Joe\Adobe Flash Builder 4.6\FlexOS Command\src\fxCommand.mxml:5]
	at flash.events::EventDispatcher/dispatchEventFunction()
	at flash.events::EventDispatcher/dispatchEvent()
	at mx.core::UIComponent/dispatchEvent()[/Users/erik/Documents/ApacheFlex/git/flex-sdk_RC2/flex-sdk/frameworks/projects/framework/src/mx/core/UIComponent.as:13688]
	at mx.core::UIComponent/set initialized()[/Users/erik/Documents/ApacheFlex/git/flex-sdk_RC2/flex-sdk/frameworks/projects/framework/src/mx/core/UIComponent.as:1839]
	at mx.managers::LayoutManager/doPhasedInstantiation()[/Users/erik/Documents/ApacheFlex/git/flex-sdk_RC2/flex-sdk/frameworks/projects/framework/src/mx/managers/LayoutManager.as:850]
	at mx.managers::LayoutManager/doPhasedInstantiationCallback()[/Users/erik/Documents/ApacheFlex/git/flex-sdk_RC2/flex-sdk/frameworks/projects/framework/src/mx/managers/LayoutManager.as:1188]
How do i fix it? Please help me! Thanks I am bit mad because code was before good working than it is not working today. I don't understand. Drive C:\ if i have installed Windows in Partition "C:\".

Thanks