Try to theme a specific page using template.php and a sub theme
This 

if ($path = 'node/131')


should surely be

if ($path == 'node/131')


Nevertheless this should not affect use of page.tpl.php.

Is your subtheme working at all, do templates get loaded from subtheme at all?

Your path is /sites/all/themes/progressive/progressive_sub. Does that mean the parent theme is at /sites/all/themes/progressive? If so, maybe try to give the subtheme a separate folder.