I had to drop support for 32Bit Macs with the latest BetterTouchTool update (because Apple seems to have decided that it’s time to move on, and many of those cool new & shiny features are only available on 64bit). As far as I know the last Macs without 64bit support where sold until 2006 or 2007. Everything that has a Core 2 Duo or newer does support 64bit.
Unfortunately the autoupdater I’m using doesn’t seem to be able to block 64bit updates on 32bit systems. So if you updated and now get an error when launching BTT, you’ll have to download an older version of BTT.
The last version that supports 32Bit can be downloaded here