how to remplace a missing composant double_fl in a structure

Hello friends,

Can anyone tell me please how to replace double_fl in this code line for an abap version 4.6C :

code from version 6 :   

DELETE lt_nodes WHERE double_fl = 'X'.

because the composant "double_fl" is missing in the structure "hier_iface" in 4.6C but it existe in version 6 .

thanks in advance .