Hey! I found a way to fix my problem, so right now you have to wait like a lot of hours, so example if the date on the iPad is 22july2012 and in the game it shows the hours you need to wait DO NOT CHANGE IT. if it is some date in the past, present of future and in the game it shows the hours you need to wait, DO NOT CHANGE IT EITHER. Then just do the date cheat where
1. Go to game
2. Exit game and fully close it (double tap home button and press the red dash)
3. Turn of Internet
4. Change the date to a future date( if your building needs 48h, forward 2days just do respectively to you situation)
5. Go to game
6. Wait till you see the retry page. DO NOT CLICK RETRY.
7. Turn on Internet
8. Go back to game.
Then your building should be built(; if you want to change your date to your present date, just go to settings and change it.
I'm using an iPad 2.