Where does "test.txt" live on your hard drive? I think you need to be a bit more explicit with the path.
You can make it "relative" to the location of your project, in case the project is run from a different workstation. I don't know python but your open call might be better done like
open(Project.Path + '\Script\test.txt')
We use Project.Path for the data files that TestComplete needs, but we also found that we needed directories that belong to our application and those can change depending on the user name or machine or other tedious things. The solution for that was to write a script that checks our app for version and user, etc., and then updates some variables like ReportPath and LogPath so we have those available for all the other tests. That script runs first in our setup routine.
