Just to be sure, there is a file called malalauncher.mplugin in the plugins directory, right?
I've never checked this myself, but I'd guess the mala log file should show something about trying to load the plugin. Does it? If so, could you post what it says here?
Also, you could try putting some other plugin in the plugins directory and see if that plugin loads properly, and let me know about that too (if other plugins don't load then obviously that would be a mala issue, and maybe the mala log file would help with that, or someone else here could).