From the help file:
Inserting an element, row, or column into an array does not change the size of the array. The trailing elements, rows, or columns are shifted toward the end of the array and the last element, row, or column in the array is dropped from it. The newly inserted element, row, or column is initialized to false (.F.).

What you should do is to make sure that the array is large enough before AINS:

DIMENSION aMyarray [2, 11]
aMyarray = "ABC"
AINS (aMyarray, 10, 2)

HTH

>I want to insert a new column to a existing 2-dimensional array. I used the foxpro function aIns() to do this:

>DIME aMyarray[2,10]
>aMyarray = "ABC"
>=aIns(aMyarray,10,2)

>The result is that the aMyarray[2,10] becomes the new value .F. instead of inserting a new column into this array.