With IFORT 10.x the compiler defaulted to 64-bit at install, but there's a script that can be run to switch the compiler to 32-bit mode.
You may want to double check to make sure that it's in 64-bit mode by executing "ifort -V"
Date: Fri, 11 Sep 2009 15:35:34 -0700
From: Doug Reeder <email@example.com>
Subject: Re: [OMPI users] OpenMPI on OS X - file is not of required
To: Open MPI Users <firstname.lastname@example.org>
Content-Type: text/plain; charset="us-ascii"; Format="flowed";
Have you checked that ifort is creating 64 bit objects. If I remember
correctly with 10.1 the default was to create 32 bit objects.