Place a support under the "Floor/Wall" area,now remove all the screws from the side wall that go threw the alum trim piece into the Floor! Now see where the screws are "Missing the edge of the floor or the floor could be Rotten" lift up the black membrane and see! If there is "Good Wood" on either side of where the BAD screw location,Drill additional holes in the Alum trim piece and add More Screws!
Youroo!!