jultaylor,
It looks as if you need to put a bit of preservative and protection on your ferret box, I would suggest a polyeuathane stained varnish.
Jamming your made net between the closed door and the door frame is not good enough to keep your meshes level. This is why your meshes have run out. Do what the other netters have said and take about 3ft of 2mm nylon drawcord and thread it through your meshes about 18" away from where you have finished tie both ends together hang over a hook or as I do, the newel post at the bottom of the stairs. Start to net and if your meshes are not level adjus