Let's pick at that prophecy a litle more, shall we?

[ffimiles]

No: HPFGUIDX 77766

> I'm with you. Obviously it is not literally true; ergo it can't be 
meant literally. 
> Perhaps JKR is using "live'' in a more figurative sense -- that 
neither of them 
> can live their destined life as long as the other one is surviving. 
LV can't 
> proceed with his evil plans freely with Harry out there causing a 
threat to his 
> future, and interfering with his plots on a regular basis. And 
Harry can't live 
> any kind of fulfilling existence with the threat of LV out there -- 
worse than the 
> mere threat, also the oppressive physical and psychological 
manifestations of 
> his intimate link with LV.
> 
> This interp is the only way i can make sense of that section of the 
prophecy.
> 
> urghiggi in Chgo

I'm not taking it literally either.  It could perhaps illude to the 
fact that neither can live as leaders - LV of the dark side Harry of 
the good.  As Harry isn't yet of age, then he isn't yet a leader/able 
to rally others.  Once he can, both sides can't 'live' in unison...am 
I rambling?  
Ffi