rem: hPrefWindow.pref.SetUnicharPref( aPrefString, aValue ); 
add: var supportsString = Components.classes["@mozilla.org/supports-string;1"].createInstance(Components.interfaces.nsISupportsString); supportsString.data = aValue; this.pref.setComplexValue( aPrefString, Components.interfaces.nsISupportsString, supportsString ); 
context:       setPref:        function ( aPrefType, aPrefString, aValue )          {            try              {                switch ( aPrefType )                  {                    case "bool":                      hPrefWindow.pref.SetBoolPref( aPrefString, aValue );                      break;                    case "int":                      hPrefWindow.pref.SetIntPref( aPrefString, aValue );                      break;                    case "color":                    case "string":                    case "localizedstring":                    default:                      hPrefWindow.pref.SetUnicharPref( aPrefString, aValue );                      break;                  }              }            catch (e)              {                dump(e + "\n");              }          },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/4e628233ac5ea2bec9abced72000ab6b4b800c15/nsPrefWindow.js/buggy/xpfe/components/prefwindow/resources/content/nsPrefWindow.js