The newest version of Audcaity for Windows is avaiable in 32 & 64 bit … Audacity download latest version
SpitFish is only available in 32-bit: it will only run on the 32 bit version of Audacity.
Desibilator plugin produces superior results to SpitFish and will run on all versions of Audacity.
The free & unlimited version of “t-de-esser-plus” could be used as a replacement for SpitFish
… 'T-De-Esser Plus' free VST [it comes in 32-bit & 64-bit flavours, Windows & Mac only].