Imam mali problem: na ekranu ništa ne vidim.

Because Serbian usually drops subject pronouns when they are not needed.

• Imam already means I have
• The verb ending -am shows the subject is I

So:

• Imam mali problem = I have a small problem
• Ja imam mali problem is also possible, but ja adds emphasis, like I have a small problem.

In neutral speech, leaving out ja is more natural.

After imam (I have), the direct object is normally in the accusative case.

Here, problem is:

• masculine
• singular
• inanimate

For masculine inanimate nouns, the accusative singular looks the same as the nominative singular.

So:

• nominative: mali problem
• accusative: mali problem

That is why nothing changes on the surface.

Compare this with an animate noun:

• Vidim malog psa = I see a small dog

There, masculine animate accusative changes.

Mali means small.

In Serbian, adjectives usually come before the noun, just like in English:

• mali problem = small problem
• velika kuća = big house

The adjective must also agree with the noun in:

• gender
• number
• case

Since problem is masculine singular here, the adjective appears as mali.

Because na can mean different things depending on whether you mean:

• location: on / at
• movement toward a place: onto / to

Here the sentence describes a location:

• na ekranu = on the screen

That requires the locative case after na.

Compare:

• Slika je na ekranu. = The image is on the screen.
• Stavio sam sliku na ekran. = I put the image onto the screen.

In the second sentence, there is movement, so na + accusative is used.

Because after na in a location meaning, Serbian uses the locative case.

So:

• nominative: ekran
• locative singular: ekranu

That is why you get:

• na ekranu = on the screen

This -u ending is very common for masculine and neuter nouns in the locative singular.

Yes, and in Serbian that is normal and required.

Serbian uses negative concord, which means that if you use a negative word like:

• ništa = nothing
• niko = nobody
• nikad = never

the verb is also negative:

• Ništa ne vidim. = I see nothing / I can’t see anything
• Nikoga ne znam. = I know nobody
• Nikad ne idem tamo. = I never go there

So unlike standard English, this kind of double negation is correct Serbian grammar.

Yes, absolutely.

Both are correct:

• Ništa ne vidim
• Ne vidim ništa

The difference is mostly about word order and emphasis.

• Ne vidim ništa often sounds more neutral to English speakers because it lines up more closely with I don’t see anything
• Ništa ne vidim puts nothing earlier, which can sound slightly more emphatic or contrastive depending on context

In everyday speech, both are common.

Vidim is the 1st person singular present tense of videti / vidjeti (to see).

So:

• vidim = I see
• ne vidim = I do not see / I can’t see

In this sentence, the speaker is describing a current ongoing situation, so the present tense is the natural choice.

A few related forms:

• videti / vidjeti = infinitive, to see
• video sam = I saw (past, masculine speaker)
• ugledati is a more punctual/perfective verb, closer to catch sight of / notice

Here, ne vidim is the normal and simplest way to say that nothing is visible to the speaker.

Yes, it is natural.

The full sentence:

• Imam mali problem: na ekranu ništa ne vidim.

sounds like a normal way to explain a technical issue.

Depending on emphasis, Serbian speakers might also say:

• Imam mali problem: ne vidim ništa na ekranu.
• Imam problem: ništa ne vidim na ekranu.
• Imam mali problem — na ekranu ne vidim ništa.

All of these are understandable and natural. Serbian word order is fairly flexible, and speakers move parts around to highlight different information.

The colon introduces an explanation of the problem.

So the structure is:

• Imam mali problem = I have a small problem
• na ekranu ništa ne vidim = explanation of what the problem is

It works like:

• I have a small problem: I can’t see anything on the screen.

In speech, you would usually make a short pause there. A dash could also work in informal writing, but the colon is clear and natural.