In addition to cronenbuilder's problem, when I click combine it pulls up my actor rather than allowing me to select another item to combine with. 
Just delete the plugin and download it again. This should work. One unpleasant bug has also been fixed in the new version.
If the problem remains, then go to the "Plugin setting", double-click on "action_name" and make it so that there are three commands. The first is responsible for using the item, the second for combining, and the third for the back. You can call it whatever you want, the main thing is the order of the commands.