buildInstrumentedMex gives "Unknown exception"

In the following code, the statement with buildInstrumentedMex gives the error "Unknown exception" while fiaccel is working fine. So the code generation must be OK. I do not have a license for code generation, but the examples from the Fixed Point Designer Getting Started Guide with buildInstrumentedMex are working fine. What am I missing?

T = mytypes('9Q23');
Hinp = cast(ones(2,2)+1j*ones(2,2),'like',T.x);
fiaccel inv4fix -args {Hinp,T} -o fiaccelinv4fix_mex
H1 = cast([ 0.1+1j*0.2 0.3+1j*0.4; 0.5+1j*0.6 0.7+1j*0.8 ],'like',T.x);
H1inv = fiaccelinv4fix_mex(H1,T);

buildInstrumentedMex înv4fix -args {Hinp,T} -histogram -o inv4fix_mex

where 
% mytypes.m
function T = mytypes(dt)
  switch dt
    case '9Q23'
      F = fimath('RoundingMethod', 'Nearest', ...
           'OverflowAction', 'Saturate', ...
           'ProductMode', 'SpecifyPrecision', ...
           'ProductWordLength', 32, ...
           'ProductFractionLength', 23, ...
           'SumMode', 'SpecifyPrecision', ...
           'SumWordLength', 32, ...
           'SumFractionLength', 23, ...
           'CastBeforeSum', true);
       T.x = fi([],true,32,23,F);
  end
end

% inv4fix.m
function Hinv = inv4fix(H,T) %#codegen
if size(H,1)==2;
    % inverse of [a b; c d] is 1/(ad-bc) [d -b; -c a]
    % fixed point types
    Tdiv = numerictype('Signed',true,'WordLength',T.x.WordLength,'FractionLength',T.x.FractionLength);
    % real algorithm
    a = cast(H(1,1),'like',T.x);
    b = cast(H(1,2),'like',T.x);
    c = cast(H(2,1),'like',T.x);
    d = cast(H(2,2),'like',T.x);
    factor = cast((a*d - b*c),'like',T.x);
    % 1/(a+1j*b) = (a-1j*b)/(a^2+b^2)
    factor_r = cast(real(factor),'like',T.x);
    factor_i = cast(imag(factor),'like',T.x);
    denominator = cast(factor_r*factor_r + factor_i*factor_i,'like',T.x);
    factor_r = divide(Tdiv,factor_r,denominator);
    factor_i = divide(Tdiv,factor_i,denominator);
    Hinv = [d -b; -c a];
    Hinv = cast((factor_r-1j*factor_i) * Hinv,'like',T.x);
else
    Hinv = H;
end

end

Answer 1

[Bert RAM Aerts]

Having two operating systems Windows 10 and Mageia 5 Linux helps sometimes... While Matlab R2015b in Windows 10 was just giving "unknown exception", Matlab R2015b in Mageia 5 was giving a clear reason "înv4fix is not a valid function name" ... Only then I saw that the first letter was not an i but î. Replacing it by a normal letter i solved this issue.