If you have a GNU/Linux version of SPSS, try the following:
strings <spss-binary> | grep x-spss
replacing the <spss-binary> with the path to the installed spss program. You might also have to search any associated libraries
which spss installs.
Alternatively, if you have a windows system with spss installed, which you can mount from GNU/Linux
You could try doing the same on the windows .exe and/or .dll - in this case, you might have to
experiment with the -e option to strings, since some windows programs encode everything in UTF16
Obviously you will need the strings program which is normally installed with the
binutils package.
J'