On a windows 8 computer using fire fox I keep getting the below error

Do you have Java installed? We have several past threads, if one uses the search feature, that discuss this issue. Follow the search results link cpt_paranoia posted in the previous post. In particular see this post I made in another thread on this same issue with Firefox for the dialog messages one should receive while accessing the WD2Go.com site if Java has been installed/activated within Firefox.