--- frmts/png/pngdataset.cpp	2011-01-14 06:19:04.000000000 +0100
+++ frmts/png/pngdataset.cpp	2011-03-01 11:41:28.762999973 +0100
@@ -1315,7 +1315,7 @@ 
     * instead of an int, which is what fread() actually returns.
     */
    check = (png_size_t)VSIFReadL(data, (png_size_t)1, length,
-                                 (VSILFILE*)png_ptr->io_ptr);
+                                 (VSILFILE*)png_get_io_ptr(png_ptr));
 
    if (check != length)
       png_error(png_ptr, "Read Error");
@@ -1330,7 +1330,7 @@ 
 {
    png_uint_32 check;
 
-   check = VSIFWriteL(data, 1, length, (VSILFILE*)(png_ptr->io_ptr));
+   check = VSIFWriteL(data, 1, length, (VSILFILE*)png_get_io_ptr(png_ptr));
 
    if (check != length)
       png_error(png_ptr, "Write Error");
@@ -1341,7 +1341,7 @@ 
 /************************************************************************/
 static void png_vsi_flush(png_structp png_ptr)
 {
-    VSIFFlushL( (VSILFILE*)(png_ptr->io_ptr) );
+    VSIFFlushL( (VSILFILE*)png_get_io_ptr(png_ptr) );
 }
 
 /************************************************************************/
@@ -1357,7 +1357,7 @@ 
     // libpng is generally not built as C++ and so won't honour unwind
     // semantics.  Ugg. 
 
-    jmp_buf* psSetJmpContext = (jmp_buf*) png_ptr->error_ptr;
+    jmp_buf* psSetJmpContext = (jmp_buf*) png_get_error_ptr(png_ptr);
     if (psSetJmpContext)
     {
         longjmp( *psSetJmpContext, 1 );