Strict Standards Error

-- url of the page with the problem -- : advancn.org/index.php?option=com_hikasho...t&Itemid=869&lang=en
-- HikaShop version -- : 2.6.3
-- Joomla version -- : 3.5.1
-- PHP version -- : 5.6
-- Browser(s) name and version -- : Chrome (most up to date)
-- Error-message(debug-mod must be tuned on) -- : Strict Standards: Only variables should be assigned by reference in /home/iamwe/public_html/templates/protostar/html/com_hikashop/checkout/listing_price.php on line 117

Strict Standards: Only variables should be assigned by reference in /home/iamwe/public_html/templates/protostar/html/com_hikashop/checkout/listing_price.php on line 208
$60.00

1
Refresh Delete
Strict Standards: Only variables should be assigned by reference in /home/iamwe/public_html/templates/protostar/html/com_hikashop/checkout/cart.php on line 744

Strict Standards: Only variables should be assigned by reference in /home/iamwe/public_html/templates/protostar/html/com_hikashop/checkout/cart.php on line 838

Hello,
I have several Strict Standards Errors on my product page and on the check out page, after a product is added to the cart.
I have a custom field attached to the order.
Products without custom fields are fine, in the shopping, but the product pages have errors
For this product I created an order field with a Single Dropdown
Goal of the field: During check out i require the customer to select their Club Identification No.
The ID No is placed in the Values Section
Example: Value 000361 | Title Chicago Edgewater ID#00361

Thanks for your help.
[img]http://advanCN.org/errors-images/Hikashop cart error.PNG
[img]http://advanCN.org/errors-images/Hikashop cart error2.PNG

Update - it seems that maybe the akeeba integration is the cause?? Products without a subscription seem to be fine.
How do i fix this error?