"Could you tell me, whether there are errors in that file?"
Translation:Ĉu vi povus diri al mi, ĉu estas eraroj en tiu dosiero?
No. The direct object of "diri" is what is said, not the person to whom it is said.
If there is no direct object, you may put the indirect object in the accusative case, so I don't see why this was rejected. For example, the following are both correct:
Mi instruas al vi Esperanton.
Mi instruas vin pri Esperanto.
What is incorrect, however, is:
Mi instruas vin Esperanton.*
Technically you're right, but I would not recommend to use accusative for indirect objects. It leads to misunderstandings and you might get mess up your feeling for verb syntaxes.
I disagree. It seems perfectly fine to me, especially when the direct object is entirely omitted.
As I said, technically you are right. Yet, for the sake of keeping good habits, I just recommend not to do it but stick to suitable prepositions. Especially as a beginner or intermediate learner.
Good point. I think in general I need to be much less cavalier about replacing just any old preposition with the accusative.
Dankon! Mi longtempe serĉis por iel, ke mi parolu kun programistoj pri malinsektigi komputilajn programaĵojn!
(Would anyone please tell me if this comment made sense?)