Can a Macbook 4,1 use 64bit architecture?
If you simply have software that needs to run as 64bit then yes it is compatible, if you have software that needs a 64bit kernel (rare) then no it is not compatible. From looking at the website where it shows system requirements it shows it needs a 64bit capable CPU, which is what your MacBook has, same CPU as my iMac. As you can see below on my Late 2006 iMac with 2GHz Core 2 Duo running 10.7.5 with a 32bit kernel and all 64bit processes.