how to resolve the following cast errors?

Error using mex
In file included from
/home/proj/elendil/peimin/Matlab_Simulink_Models/trunk/Adaptrum_Matlab_FuncLib/Viterbi/cpp_files/scanning_bit_comparator.cpp:139:0:
/home/proj/elendil/peimin/Matlab_Simulink_Models/trunk/Adaptrum_Matlab_FuncLib/Viterbi/cpp_files/errdet.cpp: In member function ?bool
ErrorDetector::scan()?:
/home/proj/elendil/peimin/Matlab_Simulink_Models/trunk/Adaptrum_Matlab_FuncLib/Viterbi/cpp_files/errdet.cpp:24:49: error: cast from
?void*? to ?unsigned int? loses precision [-fpermissive]
     unsigned txBit = (unsigned) (txData->peek(i));

                                                   ^
  /home/proj/elendil/peimin/Matlab_Simulink_Models/trunk/Adaptrum_Matlab_FuncLib/Viterbi/cpp_files/errdet.cpp:25:49: error: cast from
  ?void*? to ?unsigned int? loses precision [-fpermissive]
       unsigned rxBit = (unsigned) (rxData->peek(i));

                                                   ^
  /home/proj/elendil/peimin/Matlab_Simulink_Models/trunk/Adaptrum_Matlab_FuncLib/Viterbi/cpp_files/errdet.cpp: In member function
  ?ErrorDetectorState ErrorDetector::advance(unsigned int, unsigned int, unsigned int*)?:
  /home/proj/elendil/peimin/Matlab_Simulink_Models/trunk/Adaptrum_Matlab_FuncLib/Viterbi/cpp_files/errdet.cpp:40:29: warning: cast to
  pointer from integer of different size [-Wint-to-pointer-cast]
       txData->append((void *) txBit);

                               ^

[Walter Roberson]

On the target machine, what is the size of an unsigned int, and what is the size of a pointer?