rem: this.mPrefService.SetUnicharPref(aPrefName, aPrefValue); 
add: var str = Components.classes["@mozilla.org/supports-wstring;1"] .createInstance(Components.interfaces.nsISupportsWString); str.data = aPrefValue; this.mPrefService.setComplexValue(aPrefName, Components.interfaces.nsISupportsWString, str); 
context:   setUnicharPref: function (aPrefName, aPrefValue)    {      try        {          this.mPrefService.SetUnicharPref(aPrefName, aPrefValue);        }      catch(e)        {        }    },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/8395/faf03ce445712b372523f881cc3144cfadc7a611/nsUserSettings.js/buggy/xpfe/global/resources/content/nsUserSettings.js