This happened to me
I had this happen to me once with Dreamweaver. Not sure if it is the same thing for the WA plugin. I spoke with Adobe... was instructed to open the Windows Task Manager (ctrl-alt-delete) and click on processes tab.
I was having trouble with Dreamweaver still running but closed on my desktop. The rep instructed me to end process on dreamweaver.exe.
Not sure if that helps but... it worked for me.