product detail page not showing

-- url of the page with the problem -- : sydneymtb.org
-- HikaShop version -- : 2.4.0
-- Joomla version -- : 3.4.1
-- PHP version -- : 5.5.18
-- Browser(s) name and version -- : IE 11
-- Error-message(debug-mod must be tuned on) -- : when debug is turned off and you click a product to go to the product details page I'm getting 404 not found but if I turn debug on in Joomla it works perfectly.

i had some issues with an extension update and had to replace FoF folder. site is ok but Hikashop is doing the above,

Is the product link the same when the debug mode is turned off ?
Because I don't see why the debug would change anything.
If you disable the debug plugin via the Joomla configuration and keep the debug mode turned on, does that fix the problem ?

Debug on but plugin disabled, get blank product page again.

sydneymtb.org/member-shop/product/381-wo...g-jersey-2xu-wx1314a with debug plugin disabled blank page
sydneymtb.org/member-shop/product/381-wo...g-jersey-2xu-wx1314a with debug enabled working

Firefox shows this:
Content Encoding Error

The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression.

Please contact the website owners to inform them of this problem.

Also saw this:
Notice: Undefined index: pinterest_display in \home\site\wwwroot\plugins\system\hikashopsocial\hikashopsocial.php on line 195

Hi,

If you disable the HikaShop social networks plugin via the Joomla plugins manager, does that solve the problem ?
If you change the gzip compression setting of the Joomla configuration, does that solve the problem ?
If you turn off the "error reporting" setting of the Joomla configuration, does that solve the problem ?