Yes, there is an update for the application and it can be found on the developer's website. Access the URL below and download the HD Writer 2.6 version. Since this is an update, you will have to make sure that the previous version of HD Writer is installed on your system. The update should be applied automatically when launched.
No full version of the software is provided for download. To get support for your country, use the following URL: http://www.panasonic.com/global/support/get_support.html
Download page: http://av.jpn.support.panasonic.com/support/global/cs/soft/download/hdw26ee_w7.html