How about if you combined all the files into one text file first and then import it? If your files are like this:

C:\file1.txt
C:\file2.txt
C:\file3.txt

Use this command to combine them:

type C:\*.txt > C:\folder1\combinedfile.txt

And then import that combined file. Be careful about using the type command with wildcards like I did above. If I had put the combined file into the same directory as the other files:

type C:\*.txt > C:\combinedfile.txt

it would have actually doubled up the file because it would have put "C:\combinedfile.txt" into itself.