Why is it giving an error at the cvx end?

The code

    function Theta = cvx_solve_Theta(U,D,Theta)
NL=size(U,1);
U=U+10^(-50);
CCC=eig(U);
CCC=1.001*CCC(1);
if CCC<=0
    U=U-CCC*eye(NL,NL);
end

U=1/2*(U+U');

cvx_begin quiet
    cvx_precision low
    variable Theta(NL,1) complex;
    minimize((Theta') * U * Theta-2*real((D')*Theta))
    subject to
    for n=1:NL
        abs(Theta(n))<=1;
    end
cvx end

The error

Try a new MATLAB session. Try reinstalling CVX. Make sure you are using CVX 2.2 (not CVX 3.0beta).