o.o I think the problem is that you're planning too much. Roleplays can be unpredictable and there's no telling where things can go. Planning is nice and all, but I think it's also important to remember to be flexible. Things going in a different direction than you thought is to be expected. And the further you try to plan ahead, the more likely it is that things won't happen the way you imagined or that things will be in a completely different place than where you thought you'd be -- sort of like real life. :P So I think it's important to remember that the future plans you imagine in your head are more like possibilities than anything else. An RP isn't like writing a book -- it changes depending on where the writers want to take it. There generally isn't a set ending. Because of this, it's probably better to keep your mind open and not be so rigid about what you want to see. Otherwise, yeah, you're bound to be upset about it.
And like Minibit said -- communication. Generally, if there's something I really want to see happen, and it's near enough in the future that it would be plausible to make it work? All I have to do is send a few PM's to the right people and it isn't hard to make it work. :P If you're planning something but people don't know about it then, well, you can't expect them to be mind-readers. o.o The RP could go in a thousand different directions based on the choices the players make, and just hoping that things go in the direction you want isn't a very good strategy. Generally, though, the tiny things that create a butterfly effect to send the RP in a completely different direction are things that the RPer in question wasn't even thinking about when they posted it -- and, therefore, it's a lot easier to avoid things spinning out of control when the other players actually know what you want to do. That way, it's easy for them to take the tiny steps that they need to set these things up.
But, again, I wouldn't try so hard to plan things that are way off in the distance. There's no way you could get all those details right, and controlling every detail up until that point probably wouldn't be as fun. o.o Things that are closer to you, though? Yeah, it's fairly easy to make those happen if you just let people know about it.