Question about Vectors

[Charles via Digitalmars-d-learn]

So I was reading the documentation page: 
http://dlang.org/simd.html and noticed what appears to be a typo:

int4 v;
(cast(int*)&v)[3] = 2;   // set 3rd element of the 4 int vector
(cast(int[4])v)[3] = 2;  // set 3rd element of the 4 int vector
v.array[3] = 2;          // set 3rd element of the 4 int vector
v.ptr[3] = 2;            // set 3rd element of the 4 int vector

v.array[3] = 2; and v.ptr[3] = 2; set the fourth element, and not 
the third.

As I was verifying this, I realized I had to compile it in 64 bit 
code. The 32 bit code produced the error "SIMD vector types not 
supported on this platform".

My test code is:

     void main() {
         import std.stdio;
         import core.simd;

         int4 v = 7;
         v.ptr[3] = 2;
         writeln(v.array[]);
     }


Is that related to me compiling while using a 64 bit OS, or is 
that true of any 32 bit OS, and thus, vectors can't be used in 
programs intended to be run on 32 bit OSs?

Thanks,
Charles