Please read
this topic. As you do, bear in mind both sites seem to be run by the same people. So if there are limitations to what can be done with the allcdcovers API, and they don't even provide an API for cdcovers.cc, then there's little chance of a plugin for it being created.
In any case, you'll see my opinion is cover plugins are rather useless. Since you have to use the website interface anyway,
Web Search is the appropriate tool to use. I didn't even notice the allcdcovers plugin is not working. It's returning a "No movies found" message for every search.
