I do not know why it says this and why? It can read the 0.0000.... number and multiply with it but when dividing the number proves to be out of bounds?? and i canot seem to get around this issue with the little knowlage i have about scripting. it says 'Out of register bounds' at line 12??? according to math it should not be wrong. Urgh i do not know what the issue is any more and at this point i do not know what to do.
Please note that this might be a round about way of doing this but its how i go about learning how to script based on other scrips I've seen, and i work with a trail and error method.

alias WastePipeAnaliser d0
alias CO2Filter d1
alias H2OFilter d2
alias O2Filter d3
alias XFilter d4
alias NFilter d5
#move r5 0
#move r6 1

start:
l r0 d0 RatioCarbonDioxide
mul r5 r0 100
div r50 5 r5 <------------- This is line 12 ( I intentionally swapped the last 2 around)
div r40 r50 r0
#abs r50 r0
sne r55 r40 0
l r1 d0 RatioWater
mul r6 r1 100
div r51 r6 5
div r41 r51 r1
#abs r51 r1
sne r56 r41 0
l r2 d0 RatioOxygen
mul r7 r2 100
div r52 r7 5
div r42 r52 r2
#abs r52 r2
sne r57 r42 0
l r3 d0 RatioPollutant
mul r8 r3 100
div r53 r8 5
div r43 r53 r3
#abs r53 r3
sne r58 r43 0
l r4 d0 RatioNitrogen
mul r9 r4 100
div r54 r9 5
div r44 r54 r4
#abs r54 r4
sne r59 r44 0

l r10 d1 Power
l r11 d2 Power
l r12 d3 Power
l r13 d4 Power
l r14 d5 Power

or r61 r55 0
bgez r0 CO2
#beq r10 1 CO2a
f1:
or r62 r56 0
bgez r1 H2O
#beq r11 1 H2Oa
f2:
or r63 r57 0
bgez r2 O2
#beq r12 1 O2a
f3:
or r64 r58 0
bgez r3 X
#beq r13 1 Xa
f4:
or r65 r59 0
bgez r4 N
#beq r14 1 Na
f5:

j start

CO2:
s d1 On r61
j f1
CO2a:

j f1

H2O:
s d2 On r62
j f2
H2Oa:

j f2

O2:
s d3 On r63
j f3
O2a:

j f3

X:
s d4 On r64
j f4
Xa:

j f4

N:
s d5 On r65
j f5
Na:

j f5