Can embed code from ISSUU or any flash code into any page or post? Is allowed?
I have to use a plugging?
I have tried several times and does not work.
How can i add an audio and video player so i dont need to embed any code?

embedding things into a post or page is not under the control of the theme - this is a Wordpress function. Basic rule of thumb, if you can do it in Twenty-Ten, you can do it in Atahualpa.

You probabbly want to look for a plugin.

Go to wordpress.org and type in issuu in the search box for plugins. There are a couple that show up. Do the same search for flash.