not enough input arguments error? (fmincon)

Hello:

I tried running fmincon, but in the main program it says the function does not have enough input arguments.

f = W'*VCVMatx*W;

i=1; while i<=rows(ERGrid); ExpectedReturn = ERInc(i); [W] = fmincon('objfun',x0,swtOther_A,swtOther_b,swtOther_Aeq,swtOther_beq,swtMinWt1,swtMaxWt1,[],options); ERGrid(2:swtN+1,i) = W; i=i+1; end;

W is a 10X1 vector while VCVMatx is a 10X10 matrix.

fmincon cannot run as a result.