[vtkusers] Image reader problem

[Audi]

Hi!
I tried to run the sample code that is inside the user guide
but I cannot get the output window and it always give error
when I use the file prefix like the one inside the sample code.

this is the program that i try to run it, can anybody help me to find what
is the problem?

regards,
Audi

#include "vtkImageViewer.h"
#include "vtkImageReader.h"
#include "vtkImageMagnify.h"
#include "vtkImageShrink3D.h"
#include "vtkImageGradient.h"
#include "vtkImageDataStreamer.h"

void main( int argc, char *argv[] )
{
 int i, j;

 vtkImageReader *reader = vtkImageReader::New();
 reader->SetFilePrefix("c:/vtkdata/fullHead/headsq");  /*it prompts me error
when I use "../../../vtkdata/fullHead/headsq"*/
 reader->SetDataByteOrderToBigEndian();
 reader->SetDataExtent(0,255,0,255,1,93);
  reader->SetDataMask(0x7fff);

 vtkImageMagnify *mag = vtkImageMagnify::New();
 mag->SetInput(reader->GetOutput());
 mag->SetMagnificationFactors(3,3,1);

 vtkImageGradient *grad = vtkImageGradient::New();
 grad->SetInput(mag->GetOutput());
 grad->SetDimensionality(3);

 vtkImageShrink3D *shrink = vtkImageShrink3D::New();
 shrink->SetInput(grad->GetOutput());
 shrink->SetShrinkFactors(3,3,1);

 vtkImageDataStreamer *ids = vtkImageDataStreamer::New();
 ids->SetInput(shrink->GetOutput());
 ids->SetMemoryLimit(40000);
 ids->UpdateWholeExtent();

 vtkImageViewer *viewer = vtkImageViewer::New();
 viewer->SetInput(ids->GetOutput());
 viewer->SetColorLevel(0);
 viewer->SetColorWindow(200);

 //interact with data
 for (j=0;j<10;j++)
 {
  for (i=0; i<93; i++)
  {
   viewer->SetZSlice(i);
   viewer->Render();
  }
 }

 //Clean Up
 viewer->Delete();
 reader->Delete();
 grad->Delete();
 shrink->Delete();
 mag->Delete();

}