I am trying to install a 64bit prereq but it keeps on failing. Preq tries to check registry entry to check successful install. I think that installer is trying to find the registry entry in wow registry entry instead of actual 64bit registry space.
In condition tab you have option to set pre-requisite either for 32bit or 64 bit or default. You also have other conditions, just you have a look and set them based on your requirement.
