I found the bnb20 toolbox on
http://www.mathworks.com/matlabcentral/fileexchange/95;


I use it to solve nonlinear integer programming.


  Fist it tells me that `fun caused error.'. I set a breakpoint in the
  function m file. It tells me that ` the argument = x is undefined'.



  I can not find the answer to this problem. Please help me. Thanks,