Was this book ultimately a failure or did it contribute to the rise of modern terrorism in the seventies and eighties?

Yes and Yes.

An example from my place of expertise is the effect on the so called "Baader-Meinhof Gang."

A translated version of Marighella's book appeared in West Germany in late May of 1970. It appeared a week or two after famous journalist Ulrike Meinhof helped break notorious arsonist Andreas Baader out of police custody. They were on their path to become the world's most famous Urban Guerrillas and the Minimanual was their bible.

However, it was fairly fatally flawed in many ways; in many ways it was aspirational in nature, and not really the product of battle-tested tactics. Probably the most fatal flaw is the assumption about public support, and the need to educate them through communiques.

The Baader-Meinhof Group absolutely assumed that the public, horrified at the site of their government's "hidden fascism" would rise up from their example and attack the state independently as well. But the reality is the German people, when confronted with bombings and murder, applauded and supported their governments effort to quash them.

The minimanual was the absolute bible for many European Urban terror groups in the seventies; it's impact cannot be overstated. However they all seemed to have the same blindspot; Marighella's tactics had no real successes in South America, and had even less of a chance of succeeding First World Europe. The "proletariat of Germany had TVs, dishwashers, free education... they were not exactly fomenting revolution.

I did a podcast covering how this book influenced the Baader-Meinhof Gang, along with Frantz Fanon's the Wretched of the Earth, and Herbert Marcuse's One Dimensional Man.

https://soundcloud.com/lazespud/baader-meinhof-podcast-29-3-books-that-fomented-revolution

I also have the complete text of the minimanual in English on my site as well.