Could the white areas on either side of the page be unused portions of the canvas? If so, you could try Modify > Canvas > Trim Canvas to remove these areas, resizing the canvas. Otherwise, perhaps they're a stroke applied to an object being used as a background? If so, select the object and set its stroke to ‘None’ in the Properties panel.
Tryed trimming the canvas but nothing happens,and i checked the layers.
I should say that First the page held to the left and the white area was to the right into i centered it with html code and then there was two area's of white on either side.
OK, it sounds like you're describing an issue with how the web page looks in a web browser, not in Fireworks, after it's been exported as HTML, using either the ‘HTML and Images’ or ‘CSS and Images’ options.
Although you've already taken care of the centering issue, it looks like you could have set the alignment of the page from within the HTML Setup dialog:
Within this same dialog, there's a field for ‘Background’ but this refers to a background image. To change the background color of the page to something other than white, I'd try setting the Canvas color within Fireworks. If that doesn't work, then I'd set the background color of the <body> tag within either your CSS or HTML files (using the background-color property).