suppose I want to say: "this world, this life, I hate them". there are two ways to proceed:

{qo'vam yInvam je vImuS}
{qo'vam yInvam vImuS}

I am wondering whether the {je} is necessary, thus making the second sentence wrong.

I understand that perhaps at the second sentence one could get the meaning that "I hate this life", and being left to wonder what's the story with the {qo'vam}. but I think that context would clarify that.

or perhaps without the {je}, someone could read "I hate this life of this world". but again, would this possible ambiguity be the problem, or is there some grammar reason because of which I should use the {je} ?

perhaps I want this ambiguity, perhaps I find the feeling of this sentence to be better without the {je}..

so, all I want to know is "is the {je} necessary" ? is there some grammar reason because of which it is necessary ?

Your English original isn't "I hate this world, this life"; instead, the object of "I hate" is "them," referring to the topics you named before.

To get the same effect in Klingon, use -'e':

qo'vam'e' yInvam'e' je vImuS

Here I've made the two topics the object of the verb (but see below), in which case I definitely need to use a conjunction.

There's another way to say this:

qo'vam'e' yInvam'e' [je?] bIH vImuS

In this case, the topic words are living in the same space that locations and indirect objects live, and aren't the object of the verb (which is bIH). It's unclear whether words of the same syntactic type (in this case, topics) need to be conjoined.

But watch this: since I can elide the bIH, the sentence can look like this:

qo'vam'e' yInvam'e' [je?] vImuS

Now we see it's actually impossible to tell whether the topic words are objects of the verb or non-objects living in the "header" space. If the je is not required on like "header" words then lacking the je would force the "header" interpretation.

So the answer to your question, "is the je necessary?" is maybe.

qo' yIn je DamuSchugh bIghIQnISba'.

-- 
SuStel
http://trimboli.name