>>428
var folder = JsActions.scriptFolderPath || JsActions.getScriptFolder();
↓
var folder = _jsaCScript.currentScriptPath.replace(/[^/\\]+$/,'');
或いは
var folder = Cc['@mozilla.org/network/io-service;1'].getService(Ci.nsIIOService).getProtocolHandler('file').QueryInterface(Ci.nsIFileProtocolHandler).getFileFromURLSpec(SCRIPT_PATH[0]).path;

これでどうでしょ？