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According to Longman Dictionary of Common Errors,
Grammatically wrong: Even the teachers were prohibited to walk on the lawn.
OK: Even the teachers were prohibited from walking on the lawn.

Does it sound strange to use "...prohibited to.." instead of "...prohibited from ..ing"?
I often see "...prohibited to..." on websites apparently written by native speakers of English.
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I would say with a person, use from:

He is prohibited from X-ing

Even teachers are prohibited from walking.

With the "It" use the infinitive:

It is prohibited to walk on the lawn. But more commong: Walking on the lawn is prohibited.

It is prohibited to use foul language in chat. Using foul language in chat is prohibited.

*Maybe I'm wrong, but I think that "to" is the to of the infinitive, not a "to" of prepositions.

In those three examples, the third one sounds wrong.
Comments  
Even the teachers were prohibited from walking on the lawn.

(The sentence is correct because 'prohibited' is followed

by 'from'.)
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The "to prohibit someone/ something from doing something" is the only correct form and it must be followed by a noun/a gerund.
I wouldn't be so haisty. "Prohibit from" is the most popular version of the two, granted, but "prohibited to" turned up upward of 20 hits at COCA

Here are a few of them:

It was prohibited to use or sell precious metals

Until prohibited to do so under the 1994 amendments to the MMPA

Surely he was prohibited to mingle with the prisoners

Maybe native speakers can shed some light on which version they personally prefer. Maybe it's just a matter of choice which is correct.
I wouldn't distrust Longman Dictionary and, how did you say, coca (by the way,coca is a tropical American shrub that is widely grown for its leaves, which are the source of cocaine Emotion: big smile)... Let's wait for natives.Emotion: stick out tongue
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 BarbaraPA's reply was promoted to an answer.
to - legal abstract impersonal.

from - personal casual. as if taking away.