No sé qué le pasa a Elena, pero no quiero que ella moleste a usted.
 

So I have to correct the above sentence. I spoke to a spanish speaker and she told me this was the correct way: No sé que le pasa a Elena, pero no quiero que ella lo moleste a usted..

Shes not really into grammar though, so she couldnt explan me why. Is it correct and why?

It's correct. What, specifically, did you have a question about? Are you confused about the mixed object pronouns? If so, the verb pasar can take both a direct and an indirect object. The direct object is not being used in your sentence, but the indirect object is. The verb molestar takes only a direct object, the way it's used in your sentence, so a direct object pronoun is expected. (That said, some people would still use an indirect object pronoun.) The personal 'a' after the verb is required when the direct object is a person.

The thread title differs from the sentence you wrote in your post. Both are correct, but the first use of the word que needs an accent (not in the title sentence, but in the post). The two sentences mean slightly different things.

I was also given the senctence in Danish. In English I guess it would be: I don't know what's happening with Elena, but I don't want her to be bothering you.

Yes, I think I'm confused about the object pronouns. I thought they were only being used to replace a person/thing/etc, but I don't see what that is in this particular case?

You changed the title of the thread. The first object pronoun needs to be changed back to an indirect object pronoun (change la back to le).

pasarle algo = to have something happen to someone | to be something wrong with someone
No sé qué le pasa a Elena. = I don't know what is wrong with (happening to) Elena.

The direct object in this sentence is replaced with the relative pronoun qué. The indirect object is a Elena. The indirect object pronoun (required even though the indirect object is also stated) is le.


Pero no quiero que ella lo moleste a usted. = But I don't want her to bother you.
It's OK to keep the direct object pronoun (lo) here, even though it's redundant. (A redundant pronoun is appropriate grammar in Spanish.)
The direct object is a usted. When a direct object refers to a person, a personal a must precede it.

Okay I understand now, thanks :)