I finally had time to look through your work here.
(Have you taken this time to do so again yourself, carefully?? There is nothing going on here that requires an expert, and learning to check your work, or someone else's, is a skill worth the effort. One way to do this is to explain every step as if you were teaching someone else; and imagine that they keep asking, "why can you do that?".)
On the second page, you find angle B in triangle ABC; 53.98 is approximately correct. But then you use that as angle B in triangle BDE! That is not the same angle. From there on, you are using wrong values for both B and D.
Also, it should certainly bother you that you never used the key fact that the area of BDE is 800. If you scanned the problem at the start as you should, trying to imagine constructing the triangles, you should have seen that without this fact, the triangle is not determined.
I'm calling it your work, because whoever did it, you are implicitly approving it by saying you can't find an error.)
