[vtkusers] Help! vtkPNGReader Problem!

[n9693119 at mail.ncku.edu.tw]

I have two Linux machines, VTK was installed in machine A,
machine B used shared file system to mount $VTK_HOME directory,
When I use vtkPNGReader to load /VTKData/Data/vtk.png at machine B,
some errors appear as below:
---------------------------------------------------------------------------
libpng warning: Application was compiled with png.h from libpng-1.2.7
libpng warning: Application  is running with png.c from libpng-1.0.12
libpng error: Incompatible libpng version in application and library
ERROR: In /home/vtk/vtk-src-unix/IO/vtkPNGReader.cxx, line 56
vtkPNGReader (0x9141410): Unknown file type!
/home/vtk/vtk-src-unix/Wrapping/Tcl/vtkbase/../../../../VTKData/Data/vtk.png
is not a PNG!
----------------------------------------------------------------------------

If I convert vtk.png to vtk.bmp use some graphic convert tool,
and load vtk.bmp with vtkBMPReader at machine B,it works!

But at machine A vtkPNGReader work perfectly...
Does anybody know what's happend?