metal roof leak, plastic issue(?), and mold

Cabin roof (recreational property) was installed last July, not sure when it started leaking. May have found my leak, how should I repair? Soon as I pull the screw out, water pours in instead of dripping in. Second issue, I discovered the installers didn't remove the plastic off any of the metal. Is that going to cause me a problem? Last, and maybe for another section, I have mold starting to appear on interior wood where the water leaked in, should I spray it with water & bleach or water & vinegar? Image: http://i716.photobucket.com/albums/ww170/DCortez1960/rancho/DSCN2719_zps75ce4850.jpg