Hi it-neuss, thanks for getting in touch. To clarify you are using Per Product Shipping by WooThemes?
https://www.woothemes.com/products/per-product-shipping/
I can see that we’re expecting the PHP function woocommerce_per_product_shipping_init to exist in Per Product Shipping, it is possible that this function is no longer included and so our detection is failing.
Can you open a ticket with us via Support to send us the latest release of Per Product Shipping 🙂
