ERROR: This page is using an unprefixed version of template {{Reflist}}

Use {{Wp/pcm/Reflist}} instead and replace all occurences of {{Reflist}} in Wp/pcm/ prefixed pages by that.
You may like to check 1 template in Category:Wp/pcm/Templates using unprefixed template Reflist first to remove all occurences from those templates which will fix the pages containing those templates too.