dragging problems

Hi everyone! I have to perform a dragging experiment; I have tried to use arrays to carry out so. Anyway, when I use an array and isert the dragging part in a while cycle, it doesn't work very well; it is like it doesn't recognize the stimuli; for instance, when I have tried the experiment, at the third repetition of the while cycle, it doesn't let me to select the array stimuli that have appeared, but in contrast it let me to select CC_VUOTO stimulus, that it's not a part of the array. It even doesn't recognize the done button. I would be very grateful if someone could explain to me what I am doing wrong;


task dragging_task
set $count 0

set $number_of_bitmap 0

set &&my_array_oggetti CAFFE CALZINI_LEGEA CALZINI_POIS COLTELLI PENTOLA PORTAPOSATE 
draw off

show bitmap CC_VUOTO 15 200 
show bitmap FATTO -521 -30 
draw on

while $count < 6
set $oggetto &&my_array_oggetti remove random 1 8

set &&my_array_oggettipresentati append $oggetto

show bitmap $oggetto -521 -100 
drag option from &&my_array_oggetti

drag option xlim -600 600

drag option ylim -450 450

drag option exit 2

dragging 300000

while-end