I want to move all the tracks up by 4 bars. I select all the tracks (Ctrl A) and I move them up 4 bars. But what happens is that the tracks get duplicated. For comparison, I then go and select one single track, move it, and then it moves without duplicating. How can I move all the tracks without duplicating? Any help appreacitaed

Select everything, then Project > Insert Time/Measures

Sounds like you are holding Ctrl while you drag - you don't need to. After the tracks are selected just drag one and they will all move; if you push Ctrl when you drag they will duplicate.

it does sound like you are holding "Control".
No need to, just drag forward.

Thanks fellers for the info. Just to update, I did what Bristol Jonesy advised. I could move the clips to where I wanted to go to via Project-Insert. BUT it still split some of the clips! I had to then manually move the stray clips to where I wanted to go to - we are talking about 50 tracks here.  As for the CTL drag thing, the thing I wasn't holding down CTL at all when I was dragging. Anyway, I got there in the end. Dunno if this is a bug? 

Don't think it's a bug. Many of us do this sort of operation routinely without issue.
 
One point regarding your split clips, what I always do before a Project > Insert Time/Measures is to position the Now time where I want the split to be made, ctrl + a, then hit 's' to split all clips at that point.
Then deselect everything (ctrl + shift + a) then do the Insert
 
The only problem you might have is that any note which overlap your split will not preserve it's length with the right hand portion being discarded.
At least that's what I'm seeing on my system, don't know if there's a setting to preserve original length or not