kono mondai ha keikaku no syougai desu.

A natural reading is:

この もんだい は けいかく の しょうがい です。
Kono mondai wa keikaku no shōgai desu.

Word readings:

• この = kono
• 問題 = mondai
• は = written ha but pronounced wa here
• 計画 = keikaku
• の = no
• 障害 = shōgai
• です = desu

この means this and directly modifies the noun that follows it.

So:

• この問題 = this problem

You do not say このの問題.
Words like この, その, and あの already attach directly to a noun.

Compare:

• この問題 = this problem
• その問題 = that problem
• あの問題 = that problem over there

If this stands alone, Japanese uses これ instead:

• これは問題です。 = This is a problem.

は marks the topic of the sentence.

Here, the topic is:

• この問題は = As for this problem, ...

Then the sentence says something about that topic:

• 計画の障害です = it is an obstacle to the plan

So the structure is basically:

• Topic + comment

This is a very common Japanese pattern.

When は is used as the topic particle, it is pronounced wa.

So in:

• この問題は

you read it as:

• kono mondai wa

This is one of the standard spelling/pronunciation differences learners just have to memorize.

Here の links two nouns together.

• 計画 = plan
• 障害 = obstacle / hindrance
• 計画の障害 = obstacle related to the plan

In English, の can correspond to several relationships, such as:

• of
• for
• in
• possessive ’s

In this sentence, 計画の障害 most naturally means something like:

• an obstacle to the plan
• a hindrance to the plan

So の is not always a simple of. Its exact meaning depends on context.

Because the main idea is an A is B type statement.

The sentence says:

• この問題 = this problem
• 計画の障害 = an obstacle to the plan

So the full pattern is:

• A は B です
• As for A, it is B

Here です is the polite copula, similar to is / am / are in this kind of sentence.

They are related, but not identical.

• 問題 often means problem, issue, or question
• 障害 means obstacle, hindrance, or barrier

So in this sentence:

• この問題 = this problem / this issue
• 計画の障害 = an obstacle to the plan

The nuance is that the problem is functioning as a barrier to the plan.

One important note: 障害 can also mean disability in other contexts, so context matters a lot.

Yes, it is grammatical and understandable.

It sounds somewhat formal or written, because 障害 is a fairly formal word. In everyday speech, people might also use words like:

• じゃま = obstacle / interference
• 妨げ = hindrance
• 問題です in a different phrasing

But この問題は計画の障害です。 is perfectly valid Japanese.

Yes, but the nuance would change.

• この問題は計画の障害です。
  = As for this problem, it is an obstacle to the plan.

• この問題が計画の障害です。
  = This problem is the obstacle to the plan.

Using が puts more focus on this problem as the specific thing that is the obstacle.
Using は presents this problem as the topic and gives information about it.

For beginners, it is enough to remember:

• は = topic
• が = stronger focus/identification of the subject

Yes, but Japanese word order works differently from English.

This sentence follows a very common pattern:

• この問題 = this problem
• は = topic marker
• 計画の障害 = obstacle to the plan
• です = polite copula

So the overall order is:

• Topic + description

Unlike English, the main verb/copula usually comes at the end.
That is why です appears last.

They are probably included only to help learners see the parts clearly.

Normal Japanese is usually written without spaces:

• この問題は計画の障害です。

Adding spaces like this:

• この　問題　は　計画　の　障害　です。

is a teaching tool, not standard writing.