Thanks Product FRED but I sorted it out.
I already had the game files (including the expansion files) in the program files folder (not the x86 program files) but the game needed the registry details that install from the setup and thats why I started installing the game and its expansions again.
The problem was that I didn`t move the files in the game folder to another location before the install and the setup didn`t recognize the original zt2 or African Adventure expansion's exe and therefore didn`t let me install it, it only recognized the latest expansion exe in the old folder duh
I actually moved the game files in my previously OS install but I forgot it now
Anyway, thanks