You'll need to be already rooted to do this, and build.prop should be located somewhere in the system tree - My DROID is dead right now so I cannot say where exactly it is.
Well, not all root exploits are broken, since Superoneclick and rageagainstthecage and the manual method still work. Apparently it only breaks Zergrush.
I replied to your other post in ATR with link for the manual method - other posts in that thread have links for Super and rage.
Much appreciated ! Thank you.
Is there an easy way to unroot from that one ?