AK-index segfault

Steps to reproduce

Create a file called TESTFILE with a dictionary entry F1 of:

1: D
2: 1
3: 
4: F1
5: 5R
6: S

Now run this program to get some data in:

 open "TESTFILE" to file else stop
 
 for i = 1 to 2000
   data = i
   write data to file, "rec":i
 next i
 
 data = ''
 for i = 2001 to 2100
   write data to file, "rec":i
 next i
 
 end
 

Now

SELECT TESTFILE WITH F1 > 1500

works fine;

CREATE-INDEX TESTFILE F1
BUILD-INDEX TESTFILE F1
SELECT TESTFILE WITH F1 > 1500

Segfault.