For some reason, your responses.xls file was actually called responses.xls.xls

Try renaming it responses.xls. Your system may have the option to "view file extensions" turned off (see the setup section in the help guide for how to turn it on). Without this option, you normally wouldn't see the final ".xls"

With file extensions turned off, you would actually want it to appear to be called "reponses". That will at least enable you to use the responses.xls file functions. Then if you still have any trouble with it, let us know.