"This file is not in a recognizable format" message

[a_en]

I've been using DirectRT collecting data and it works perfectly most of the time. However, some DirectRT output files (.csv files) from a latest round of data collection seem to be "naughty." Double-clicking any of these files pops up a dialogue window saying "This file is not in a recognizable format. If you know the file is from another program which is incompatible with Microsoft Office Excel, click Cancel, ... If you still want to see what text is contained in the file, click OK. Then click Finish in the Text Import Wizard."

It appears to be an empty file when I click OK though.

Would anyone please let me know if there is any solution to this problem？ Great thanks.