Satimage osaxen appear to be 32-bit only. I suggest contacting Satimage directly to find out if/when a 64-bit version will be available. In the meantime, any applications that you use to run 32-bit osax commands will need to be set to run in 32-bit mode themselves if they aren’t already (see File → Get Info in Finder).
TextCommands is also 32-bit only, but it’s a scriptable faceless background application, not an osax, so runs as an independent process. Therefore, it doesn’t matter if the applications using it are 32- or 64-bit. If you have a problem using TC on 10.6, please file a bug report containing as much information as possible (hardware, OS configurations; any error reports appearing in the GUI, calling script, and/or Console logs).