You could probably run the game on x64 without the AMD 64 patch, but I wouldn't know since I automatically installed the patch when I installed the game.
I usually install the patches one at a time (no reason), so that's how I found out that the 1.4 screws things up when you install it on top of the AMD x64 patch.
My suggestion though (for 64-bit) would be to install the game, patch 1 & 2, then the AMD 64 patch and contents. That's it, Leave the 1.4 patch out and you should be good to go.
Or you could just intall the game and the cumlative 1.4 patch and leave the AMD 64 patch alone, but I haven't done it this way so...