This message is not grammatically wrong. This particular usage of the genitive is called w:de:Genetivus subiectivus. Your suggestion is adds confusion because it only partly replaces the genitive, while keeping the genitive "verbundener und benachbarter Rechte".
While the message is grammatically correct, it is very badly written and almost incomprehensible. I am not sure how to find out the context where it appears so we can find a more comprehensible wording.
As I did not argue at any point that the message text was grammatically wrong, I really don't see your point in defending the grammar. The grammar is not the problem here, the problem is the content. The message text conveys a wrong statement about the legal situation. The very information given by this message text is false.
The grammer is the content is the grammar. «Einschränkungen des Urheberrechts» can mean either ‘restrictions under the law’ (genitivus subiectivus) or ‘restrictions to the law’ (genitivus obiectivus). The latter just couldn’t possibly make any sense, so it is pretty obvious that it must be the former.
The current translation is very ungrammatical: «Diese Datei wurde festgestellt als frei von bekannten Beschränkungen [...].» The predicate «wurde festgestellt» cannot take «diese Date» as a subject.