html and custom layout

I am having some 10-15 html pages.
From one html page I have to access another html page which is done using href...

Now I am showing this html content using custom layout and opening it in a new window.
The html page opens correctly, but when I click on another html href link, it doesn't work.

Also for each time I open html in a new window the url appends a digit which increments every time i open a new window.

And when I viewed the html source found that the file path is something different....

Is there any solution for this.....