My house has a concrete block foundation. We had a 6ft window installed near the walkout door. They built the hole for the window when laying the blocks. They then put treated lumber in the hole, followed by the window, which appears to be a standard vinyl window. On the outside the siding guy made a frame out of aluminum flashing or fascia material. This arrangement is leaking. I have tried calking around it several times, but it still leaks pretty badly.

Any ideas on how to seal this up? Do I need to remove this flashing/fascia type material and replace with something different?

J.Coyne