"She received a flower from her friend."
Translation:Sie erhielt eine Blume von ihrem Freund.
You’re right, von is necessary (regardless if you use bekommen or erhalten). So your version should be accepted – with the caveat that it’s not the neutral word order. That would be Sie erhielt eine Blume von ihrem Freund. If that word order seems a little strange (normally adverbs come before objects after all), I think this is actually one noun phrase (what kind of flower? A flower from her boyfriend) rather than a two separate phrases.
That’s a very marked sentence order – meaning it might be ok in certain special situations (in this case for example if you’re making a contrast: “Eine Blume bekam sie von ihrem Freund, aber Pralinen von ihren Kollegen” – and even that’s a bit odd because you would usually expect definite nouns as the object then) but outside of those situations it would sound weird.
I am only a poor, confused German learner and enjoying every minute of living Germany. However Duolingo can be confusing sometimes, 'insisting' on a certain tense or word order in some cases, but other times flexible. It is a great program and for free. It is always interesting to know the deeper meaning of sentences. So thanks for the explanation! Maybe more examples will help my fellow learners.
That’s not flat out wrong (except for the lack of capitalisation on Freund) but it doesn’t sound natural like this. The only context I can think of where I would use that word order is if you’re contrasting different presents she received from different people: Sie erhielt von ihrem Freund eine Blume und von ihrem Vater Süßigkeiten. And even then I still somewhat prefer the object directly after the verb. (Also erhalten is quite formal; bekommen sounds more natural in an informal context like this. But that’s a different topic ;) )
There is no dative object here, just an accusative one (eine Blume). Von ihrem Freund is just a prepositional phrase, not an object, just like in der Schule. Also even if it was a prepositional object (German has these too, e.g. an jemanden glauben, just like English also does: “to believe in somebody), that would still count as a prepositional object, regardless of what case the preposition forces on the noun. The important thing would be the preposition; the noun’s case is just a byproduct of the preposition.
It is, but ihrem Freund is not directly subordinate to the verb, so it’s not an object. It’s part of the phrase von ihrem Freund, and it’s the preposition von which caused the dative.
You could say the verb goes: “I want an object in accusative, and if you also want to give me a von, that’s fine.” And then the von goes: “I’m too shy, I’m not going unless you give me a noun as company, and also that noun has to be in dative case.” The verb doesn’t care about the noun that goes with von. At most it cares about whether or not it gets a von to play with, and even there it has a “I’d take it but I don’t need it” attitude. The noun in dative case is just a condition von has if you want it to show up at all.