The error is:

??? Error using ==> mupadinit at 35

Unable to initialize kernel

Error in ==> mupadengine.mupadengine>mupadengine.evalin at 119

[res,status] = mupadmex(statement);

Error in ==> mupadengine.mupadengine>mupadengine.feval at 157

[S,err] = evalin(engine,stmt);

Error in ==> mupadfeval at 24

[S,err] = feval(symengine,cmd,varargin{:}); % returns sym

Error in ==> sym.plus at 27

X = mupadfeval('_plus',A(:),B(:));