You can't import the spinorama data for two reasons:
1. The data is in a format that REW cannot parse. All of the files are in multi-column, tab separated text files that need to be imported into a spreadsheet and then exported as multiple files for each column pair of frequency and magnitude.
2. All the files have a comma in all frequency values above 1000 Hz. The values appear as 1,000, 2,000, etc. which causes REW to throw the error below. To avoid the error you have to edit all the text files to remove the comma from all frequency values.
View attachment 62354
You will get a better representation of the spinorama data by using
the MatLab/GNU Octave scripts from user Maiky76 over on ASR.