Thanks Andre, I played with the settings and managed to work it out. I was using the default "csv-excel" export template which creates a csv file, not a text file. When I double-clicked on the created csv file, it opened in Excel and I encountered the problem described. I guess the problem was that I had my computer automatically open csv files in Excel, when it should have been opening them in Notepad.
Anyway, the export script for the alternative "csv-simple" template also includes "$file_name TrackList.csv". I had to change this to "$file_name TrackList.txt" in order to force TagScanner to create a text file. When I do this, export using the "csv-simple" template and import the resulting text file into Excel using the method you describe, the problem is solved. Thanks again.