When running a 64-bit OS, you are asked if you optionally want to install the 32-bit files; that way you can have both versions. The 64-bit version gets installed in the Program Files/Smith Micro/Poser Pro 2010 folder, and the 32-bit files, if selected,  are installed in the Program Files (x86)/Smith Micro/Poser Pro 2010  folder.

If you're running a 32-bit OS (I'm going by memory here, it's been a while), there is no option to install 64-bit files. It ONLY installs 32-bit files, and they are installed to Program Files/Smith Micro/Poser Pro 2010 (32-bit systems do not have a Program Files (x86) folder).