diff --git a/Modules/DiffusionImaging/FiberTracking/IODataStructures/FiberBundleX/mitkTrackvis.cpp b/Modules/DiffusionImaging/FiberTracking/IODataStructures/FiberBundleX/mitkTrackvis.cpp
index 853dd2fc1f..1b6a70d56c 100644
--- a/Modules/DiffusionImaging/FiberTracking/IODataStructures/FiberBundleX/mitkTrackvis.cpp
+++ b/Modules/DiffusionImaging/FiberTracking/IODataStructures/FiberBundleX/mitkTrackvis.cpp
@@ -1,186 +1,191 @@
 #include <mitkTrackvis.h>
 
 TrackVis::TrackVis()  { filename = ""; fp = NULL; maxSteps = 20000; }
 
 TrackVis::~TrackVis() { if (fp) fclose( fp ); }
 
 
 // Create a TrackVis file and store standard metadata. The file is ready to append fibers.
 // ---------------------------------------------------------------------------------------
 short TrackVis::create(string filename , itk::Size<3> size, itk::Point<float,3> origin)
 {
     // prepare the header
     for(int i=0; i<3 ;i++)
     {
         hdr.dim[i]            = size.GetElement(i);
         hdr.voxel_size[i]     = 1;
         hdr.origin[i]         = 0;
     }
     hdr.n_scalars = 0;
     hdr.n_properties = 0;
     sprintf(hdr.voxel_order,"RAS");
     sprintf(hdr.pad2,"LPS");
     hdr.image_orientation_patient[0] = 1.0;
     hdr.image_orientation_patient[1] = 0.0;
     hdr.image_orientation_patient[2] = 0.0;
     hdr.image_orientation_patient[3] = 0.0;
     hdr.image_orientation_patient[4] = 1.0;
     hdr.image_orientation_patient[5] = 0.0;
     hdr.pad1[0] = 0;
     hdr.pad1[1] = 0;
     hdr.invert_x = 0;
     hdr.invert_y = 0;
     hdr.invert_z = 0;
     hdr.swap_xy = 0;
     hdr.swap_yz = 0;
     hdr.swap_zx = 0;
     hdr.n_count = 0;
     hdr.version = 1;
     hdr.hdr_size = 1000;
 
     // write the header to the file
     fp = fopen(filename.c_str(),"w+b");
     if (fp == NULL)
     {
         printf("[ERROR] Unable to create file '%s'\n",filename.c_str());
         return 0;
     }
     sprintf(hdr.id_string,"TRACK");
-    fwrite((char*)&hdr, 1, 1000, fp);
+    if (fwrite((char*)&hdr, 1, 1000, fp) != 1000)
+      MITK_ERROR << "TrackVis::create : Error occurding during writing fiber.";
 
     this->filename = filename;
 
     return 1;
 }
 
 
 // Open an existing TrackVis file and read metadata information.
 // The file pointer is positiond at the beginning of fibers data
 // -------------------------------------------------------------
 short TrackVis::open( string filename )
 {
     fp = fopen(filename.c_str(),"r+b");
     if (fp == NULL)
     {
         printf("[ERROR] Unable to open file '%s'\n",filename.c_str());
         return 0;
     }
     this->filename = filename;
 
     return fread((char*)(&hdr), 1, 1000, fp);
 }
 
 
 
 // Append a fiber to the file
 // --------------------------
 short TrackVis::append(mitk::FiberBundleX *fib)
 {
     vtkPolyData* poly = fib->GetFiberPolyData();
     for (int i=0; i<fib->GetNumFibers(); i++)
     {
         vtkCell* cell = poly->GetCell(i);
         int numPoints = cell->GetNumberOfPoints();
         vtkPoints* points = cell->GetPoints();
 
         unsigned int     numSaved, pos = 0;
         //float* tmp = new float[3*maxSteps];
         std::vector< float > tmp;
         tmp.reserve(3*numPoints);
 
         if ( numPoints > maxSteps )
         {
             printf( "[ERROR] Trying to write a fiber too long!\n" );
             return 0;
         }
 
         numSaved = numPoints;
         for(unsigned int i=0; i<numSaved ;i++)
         {
             double* p = points->GetPoint(i);
 
             tmp[pos++] = -p[0];
             tmp[pos++] = -p[1];
             tmp[pos++] = p[2];
         }
 
         // write the coordinates to the file
         if ( fwrite((char*)&numSaved, 1, 4, fp) != 4 )
         {
             printf( "[ERROR] Problems saving the fiber!\n" );
             return 1;
         }
         if ( fwrite((char*)&(tmp.front()), 1, 4*pos, fp) != 4*pos )
         {
             printf( "[ERROR] Problems saving the fiber!\n" );
             return 1;
         }
     }
 
     return 0;
 }
 
 
 
 //// Read one fiber from the file
 //// ----------------------------
 short TrackVis::read( mitk::FiberBundleX* fib )
 {
     int numPoints;
     vtkSmartPointer<vtkPoints> vtkNewPoints = vtkSmartPointer<vtkPoints>::New();
     vtkSmartPointer<vtkCellArray> vtkNewCells = vtkSmartPointer<vtkCellArray>::New();
 
     while (fread((char*)&numPoints, 1, 4, fp)==4)
     {
         if ( numPoints >= maxSteps || numPoints <= 0 )
         {
             printf( "[ERROR] Trying to read a fiber with %d points!\n", numPoints );
             return -1;
         }
         vtkSmartPointer<vtkPolyLine> container = vtkSmartPointer<vtkPolyLine>::New();
 
         float tmp[3];
         for(int i=0; i<numPoints; i++)
         {
-            fread((char*)tmp, 1, 12, fp);
+            if (fread((char*)tmp, 1, 12, fp) == 0)
+              MITK_ERROR << "TrackVis::read: Error during read.";
+
             tmp[0] = -tmp[0];
             tmp[1] = -tmp[1];
             vtkIdType id = vtkNewPoints->InsertNextPoint(tmp);
             container->GetPointIds()->InsertNextId(id);
         }
         vtkNewCells->InsertNextCell(container);
     }
 
     vtkSmartPointer<vtkPolyData> fiberPolyData = vtkSmartPointer<vtkPolyData>::New();
     fiberPolyData->SetPoints(vtkNewPoints);
     fiberPolyData->SetLines(vtkNewCells);
     fib->SetFiberPolyData(fiberPolyData);
 
     return numPoints;
 }
 
 
 
 // Update the field in the header to the new FIBER TOTAL.
 // ------------------------------------------------------
 void TrackVis::updateTotal( int totFibers )
 {
     fseek(fp, 1000-12, SEEK_SET);
-    fwrite((char*)&totFibers, 1, 4, fp);
+    if (fwrite((char*)&totFibers, 1, 4, fp) != 4)
+      MITK_ERROR << "[ERROR] Problems saving the fiber!";
 }
 
 
 void TrackVis::writeHdr()
 {
     fseek(fp, 0, SEEK_SET);
-    fwrite((char*)&hdr, 1, 1000, fp);
+    if (fwrite((char*)&hdr, 1, 1000, fp) != 1000)
+      MITK_ERROR << "[ERROR] Problems saving the fiber!";
 }
 
 
 // Close the TrackVis file, but keep the metadata in the header.
 // -------------------------------------------------------------
 void TrackVis::close()
 {
     fclose(fp);
     fp = NULL;
 }