rem: this.mPrefs = XPCU.getService("@mozilla.org/preferences;1", "nsIPref"); 
add: var prefService = XPCU.getService("@mozilla.org/preferences-service;1", "nsIPrefService"); this.mPrefs = prefService.getBranch(null); 
context:   init: function()  {    this.mPrefs = XPCU.getService("@mozilla.org/preferences;1", "nsIPref");  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/73c9a1111f3d6e085e25cfcd0d150659488f11a0/PrefUtils.js/buggy/extensions/inspector/resources/content/jsutil/system/PrefUtils.js