APEX

In the application builder, I click on an application and choose Details in View.
I get the list of pages I have in my app.
The page type column has:

Interactive Report
Navigation Form
Dynamic HTML
DML Form
Chart
Report
...

How do I change this column after a page has long been created?
Specifically, I want to the change "Dynamic HTML" to something else.

Why?
Because on this particular page, tabs do not work (error: page not found).
Buttons created among a regions items do not work (same error, page not found).
I need to use tab and buttons to go from this page to other pages.
And I am suspecting the page type may have something to do with my problem.

Thanks in advance for any pointers.