I'm sorry for the difficulty here.
I think there's some confusion over what a Session Script is and what it can do.
A session script will attempt to recreate a JMP session as it is at the moment that you save the session script. It does this by examining all open windows and asking them for a script to reproduce them.
JMP does not keep any kind of log or script of everything you do while running JMP. So, if you open a data table, created a subset and save it, and then close the original and save a session script the session script will only know about the subset. When the session script is run it will attempt to open the table from it's saved location. It won't open the original data table and do the subset.
If you need a script to open a data source and do analyses on updated data you'll need to assemble that script yourself.
Start by capturing the Source scripts in data tables and putting them in a script window. You can also save the scripts for any analyses to the script window.
To learn more about JMP scripting I recommend you watch Automating Analysis and Reporting Using JMP Scripts from the Mastering JMP webcast series.
-Jeff
-Jeff