sentence  problem
Kann daher nicht großen Kummer von Ihnen erwarten.

Why it isnt: Kann daher nicht einen großen Kummer erwarten.

Is this in the first sentence Nullartikel, if so, when to use that?

Rather "kann daher keinen großen ...", but why doesn't the sentence have a subject? It sounds a bit like telegram style, so it's a bit difficult to discuss such details. Do you have some context?