There is a documentation inside the zip file you download from the codecanyon. When you unzip it, there must be also a documentation.zip file inside of it. (at least this is how I upload it to codecanyon, it is required)
However this is not a known issue, most likely a conflict with another plugin or template. Can you please provide temporary ftp/administrator access to the website? I will take a look at the problem myself and fix it if possible asap.
You can add the website details if you edit your first post in this thread, so nobody else will see them, only me and you.