Memory bank displays are blank

Program:

mov r1 10[item=iron-plate]
mov r2 20[item=copper-plate]
mov r3 300[item=steel-plate]

mov r5 2
mov r6 r@5 # r6 will be equal to r2, which is 20[item=copper-plate]
mov r4 m1@5 # r4 will be equal to mem1[2]

mov r5 3
mov r7 r@5 # r7 will be equal to r3, which is 300[item=steel-plate]
mov r4 m2@5 # r4 will be equal to mem2[3]

mov r5 5
mov r8 r@5 # r8 will be equal to r5, which is 5
mov r4 m3@5 # r4 will be equal to mem3[5]