It's not going to work because array created by ADIR is two-dimentional. It should be

= STRTOFILE(FILETOSTR(gaText[i,1]), "orders.txt",.t.)

>

>gnNumber = ADIR(gaText, '*.txt')
>
>nqty = alen(gaText,1)
>FOR i = 1 TO nqty
>    ? STRTOFILE(FILETOSTR(gaText(i)), "orders.txt",.t.)
>ENDFOR

>
>