This is unlikely to have anything to do with the <batch> elements / the <batch> script per se. You posted in the Inquisit 3 forum, so I assume you are trying to run this using Inquisit 3 Web. Inquisit 3 Web won't work under some current browsers (e.g. Chrome) because those browsers do not support plugins anymore. Also, Inquisit 3 has not been tested under the most recent Windows versions and OSX is not supported at all. If you find a compatible computer (running e.g. Windows 7) and use Internet Explorer to run the study, it will probably work just fine.
If you need support for current browser versions, current Windows versions as well as Macs, you would have to consider upgrading to Inquisit 4 Web.
Hope this helps.