Values of V and abm

[asha g]

I am having some problems in a program I have written. It is pretty long. But 
the section is :

N = 10;
niter = 10000;
for iter = 1: niter

[P,S] = timedepcabactoct(Q,V,h2,Iion,deltaT);
for jj = 2:N-1
V(jj) = S(jj);
end 
if deltaT*niter < 5
I = 0;
elseif 5 == deltaT*niter <= 55
I = 48.4*10^-12;
V(1) = V(2)+(Ri/Ao)*I*hd;
V(N) = 4/3*V(N-1)-(1/3)*V(N-2);
end
disp(V)
calling function ratcon2oct
[alphan,betan,alpham,betam,alphah,betah] = ratcon2oct(V);
abm = alpham +betam;
m = m+(deltaT.*(alpham -m.*abm));
abh = alphah + betah;
h = h +(deltaT.*(alphah-h.*abh));
abn = alphan + betan;
n = n + (deltaT.*(alphan-n.*abn));
end 
abmm(iter,:)= abm;
abnn(iter,:)= abn;
abhh(iter,:)= abh;
abm1= abmm(iter,1);
t = (1:niter)*deltaT;
plot(t,abm1)

warning: implicit conversion from real matrix to real scalar


I need to get an oscillating plot of abm1, abn1 and abh1 vs t. But I don't. 
Instead I get the warning given above which I don't follow. Also, if I try to 
check V at the point indicated I get the vector V repeated (N-2) times before 
the values change. I would have expected it to change at every iter count. 
Please tell me if I am writing the loop incorrectly. 

Thanks
Asha