Kommiku is a Online Media Viewer.
Make sure the directory for that Comic Base does not exist. For example, if I had the directory called "Manga" in my root files, and my Comic Base as "Manga", the directory folder will override WordPress's Hook, and you will be going to the directory instead.
Okay! Last but not least... make sure your WORDPRESS PERMALINK are not on "default". You know when you get http://example.com/?p=321 . Well... thats default. Only prerequiste is that you change the permalink to something else.
When you create a zip file. Make sure there are only images in that zip file. There can be one or more folder, but it may make the source of the image look ugly.