Neil,
Try to run this code :

SELECT modacad.key1, modacad.key2, modacad.key3, modacad.key4, modacad.mainkey ;
FROM "U:\Data\modacad.dbf" ORDER BY modacad.key1 ;
WHERE modacad.key4='TECHNICAL' or modacad.key4='SAMPLE' ;
INTO CURSOR result