I agree with Trailblazer, try and find the leak source if you can before sealing it up. Looking at the screws along the sides, that can and has been a source of leak intrusions. Take a real good look in that area. On any suspect ones take the screw out. If it is rusted heavy or worse goo'ey, water had entered that screw location. How much moisture, do not know. Maybe a little or a lot.
The putty tape behind it may have broke down over the years and water can wick in around the screw, rust the screw and rot the wood and just keep going with the water entry.
See this ugly pic of my buddies new 2 year old camper due to wicking screws as the manufacture did not put Dicro caulk in the right place along the gutter rail. Good for my bud the manufacture paid to replace the entire roof, back and one side of the camper.
I also just caught one of my screws that had started wicking. On the newer campers they hid the screws behind a vinyl cover. Water gets in behind the vinyl over time, festers and molds up.
Here is the one screw I caught just in time.
The screw on the left has a little goo on it from wet wood.
You can see here the difference. While this screw has a rusted head the threads are clean with no water intrusion.
On the Eternabond tape, yes it does adhere to aluminum as I have it applied there and the manufactures sites talks of it as well. See this post of mine it may be of some help. Heads up, the surface has to be cleaned and prepped correctly before applying.
Now to what to coat the roof with once you seal up the leak and after you are going to do any Eternabonding. I myself have not done a metal camper roof but have mobile home roof and I have heard and read the process can be the same. From the lumber yard they sell a silver fiber filled roof coating for metal roofs. It is like spreadable tar with fibers in it. You use a pole brush and handle to apply with.
This has been talked about here on the forum before. Member Steve Collins (also screen name) I believe has done this before. Try searching on roof or coating may turn up those posts.
A heads up, odds are very high your roof in not a walk on roof. They where special order to get them. You either hang over from each side or get pieces of 1/2" or thicker plywood wide enough to span the 16" on center rafters. While I have a rubber roof the same problem exists. I use 24" wide 5/8" pieced of plywood placed over the rafter to kneel on. And a tarp under the wood, in my cast to protect the rubber but it could help aluminum as well from dirt impressions.
Get a good ladder, solid on good footing
And place plywood sheets as needed to spread the load. I can fell the rafters under the roofing so I know where to place them. This is when I was working on my AC unit.
Hope this helps and good luck. And please post back and with pics if possible on what you find and how you worked through it. It will help folks in the future big time.