I define on the "Category
view options" the Title to be "Show" and I cant see on the category page on the top ot the page the Title of category.

Have you created an override for the k2 component template? Recheck the parameters you have set and try browse a category with the default settings to see if you see it then.

I have create a new template. Also I use the default template and also I can' t see the title of the category on the top of the page.
Can you tell me how the category title is calling on the category_item.php file. (It could be possible to be deleted :) )