Реестровую ошибку и сервитут надо указать не позднее чем утром.

They are both in the accusative case because they are the direct objects of указать (to indicate / specify / state).

• ошибка is a feminine noun, so in the accusative singular it becomes ошибку.
• The adjective реестровая also has to match it, so it becomes реестровую.
• сервитут is a masculine inanimate noun. For masculine inanimate nouns, the accusative singular is usually the same as the nominative singular, so it stays сервитут.

So:

• nominative: реестровая ошибка
• accusative: реестровую ошибку

and

• nominative: сервитут
• accusative: сервитут

Надо is an impersonal word of necessity. It means something like:

• it is necessary to
• one must
• it is required to

So надо указать literally means it is necessary to indicate/specify.

There is no explicit subject here. Russian often leaves it general:

• Надо указать... = It is necessary to indicate... / You need to indicate...

If you want to say who has to do it, Russian can add a dative:

• Мне надо указать... = I need to indicate...
• Вам надо указать... = You need to indicate...

In your sentence, the subject is just understood from context.

Russian uses the perfective infinitive указать because the sentence is about a required completed action by a deadline.

• указывать = imperfective, more like to be indicating, to indicate in general, or to indicate repeatedly
• указать = perfective, to indicate once and get it done

Since the sentence includes a deadline:

• не позднее чем утром = no later than in the morning / by morning

the idea is that the action must be completed by that time. That is why указать is the natural choice.

Because реестровую only modifies ошибку, not сервитут.

The structure is:

• реестровую ошибку = the registry error
• и сервитут = and the easement

So the sentence is talking about two different things that must be specified:

1. реестровую ошибку
2. сервитут

If the adjective applied to both nouns, Russian would usually need a different structure, and in this case it probably would not make sense anyway, because реестровый naturally goes with ошибка, not with сервитут.

Не позднее чем is a set expression meaning no later than.

Examples:

• не позднее чем завтра = no later than tomorrow
• не позднее чем в 10 часов = no later than 10 o’clock
• не позднее чем утром = no later than in the morning / by morning

A very similar and common alternative is не позже чем. In many contexts, the two mean basically the same thing.

So in your sentence, this phrase sets the latest acceptable time for the action.

Утром is the instrumental case, but here it functions as an adverbial time expression meaning in the morning.

Russian commonly uses certain nouns of time in this way:

• утром = in the morning
• днём = during the day / in the daytime
• вечером = in the evening
• ночью = at night

So не позднее чем утром means something like no later than the morning or by morning.

You may also see other time constructions, for example:

• не позднее утра = no later than morning

That uses a different grammar pattern, but the general meaning is close.

Yes, the sentence could also start with Надо указать.

Russian word order is more flexible than English word order. The sentence you have:

• Реестровую ошибку и сервитут надо указать не позднее чем утром.

puts the objects first, which can make them feel more prominent or already known from context.

A more neutral order in some contexts might be:

• Надо указать реестровую ошибку и сервитут не позднее чем утром.

Both are grammatical. The difference is mostly about focus and information structure, not basic meaning.

This is a very common question for learners.

Сервитут is:

• masculine
• singular
• inanimate

For most masculine inanimate nouns, the accusative singular is identical to the nominative singular.

So:

• nominative: сервитут
• accusative: сервитут

Compare that with an animate masculine noun:

• nominative: студент
• accusative: студента

So the reason сервитут does not visibly change is that it follows the normal masculine inanimate pattern.

Сервитут is a legal term. It means easement, that is, a legal right to use someone else’s land or property in a limited way.

It is not especially common in everyday conversation, but it is normal in:

• legal language
• property law
• land registration / cadastral documents

For a learner, the important grammar point is that it behaves like a regular masculine inanimate noun.

Here и simply means and, so it means both items must be indicated:

• реестровую ошибку
• сервитут

If Russian wanted to say either one or the other, it would use something like или (or), not и.

So the grammar clearly presents these as two coordinated objects of the same verb указать.