The .ssp files store the path of the audio file used in the .ssp or Song Surgeon project file.

If you have moved these audio files or moved .ssp's to a new machine, the .ssp's will not be able to
open.   You will need to restore the audio files to the original location or change the location fo the
files in the .ssp.

If you have have these audio files on the new machine and need to change the path in the .ssp file
then you will need to manual open each .ssp file. You should use either Word Pad or Note Pad.
When you open them you will see something like this.

audio_file_path "C:\Users\toddason\Song Surgeon 4\Projects\building-for-life-Copy000001.wav"

You will need to change this path to the correct location on your new machine.