The Lond Daer ones are inconsequential because it is not in progress, and is old and outdated anyway. With the Helms Deep one, are you using Rohan pack? I don't believe there are any white blocks, but you never know. Another thing to be sure of is that you warp to Helms Deep, not xHelms Deep. That could be your problem too.You can't access to te top of the Tower of Ecthelion because there's one ladder missing :
Anthother thing about MT, if I can ask something for me, where is the Palantír ?
Also, the water is strange under the collapsed tower (the one near the bridge just beside the wall) in Lond Daer :
One last thing : it seems to be finished, so why did you left all these white blocks in Helm's Deep ?