The reassembler simply concatenates (adds together) the five parts into one file. It does not alter the parts in any way.
copy /b PSV0.2.010.Part1 + PSV0.2.010.Part2 + PSV0.2.010.Part3 + PSV0.2.010.Part4 + PSV0.2.010.Part5 PlaneShiftV0.2.010.exe
^^ that is the command that runs inside the batch file. If that does not work, then you have a serious issue somewhere. If it does work but the .exe doesn\'t do anything then one or more of the parts are corrupted