Well, to be honest, I prefer native speakers' answers. If you haven't got the time to read the whole discussion or at least part of it to get what makes English speakers think this sentence is not grammatical, you then will always think it's entirely correct. That's my point.
Furthermore, I'd say that sentence of yours was correct too. At least, for the British In AmE I'd say I'm going to go there tomorrow.
I think we should move this thread to "English for Russians".