diff --git a/lib/gpx/gpx_file.rb b/lib/gpx/gpx_file.rb
index 03bfd99..6fe8b74 100644
--- a/lib/gpx/gpx_file.rb
+++ b/lib/gpx/gpx_file.rb
@@ -54,13 +54,12 @@ module GPX
               gpx_file = gpx_file.name if gpx_file.is_a?(File) 
               @xml = XML::Document.file(gpx_file)
             else
-              parser = XML::Parser.new
-              parser.string = opts[:gpx_data]
+              parser = XML::Parser.string(opts[:gpx_data])
               @xml = parser.parse
             end
             # set XML namespace for XML find
-            if @xml.root.namespace_node
-              @ns = 'gpx:' + @xml.root.namespace_node.href
+            if @xml.root.namespaces.namespace
+              @ns = 'gpx:' + @xml.root.namespaces.namespace.href
             else
               @ns = 'gpx:http://www.topografix.com/GPX/1/1'  # default to GPX 1.1
             end
@@ -197,8 +196,8 @@ module GPX
       # you modify the GPX data (i.e. by adding or deleting points) and you
       # want the meta data to accurately reflect the new data.
       def update_meta_data(trk, get_bounds = true)
-         @lowest_point   = trk.lowest_point if(@lowest_point.nil? or trk.lowest_point.elevation < @lowest_point.elevation)
-         @highest_point  = trk.highest_point if(@highest_point.nil? or trk.highest_point.elevation > @highest_point.elevation)
+         @lowest_point   = trk.lowest_point if(@lowest_point.nil? or (!trk.lowest_point.nil? and trk.lowest_point.elevation < @lowest_point.elevation))
+         @highest_point  = trk.highest_point if(@highest_point.nil? or (!trk.highest_point.nil? and trk.highest_point.elevation > @highest_point.elevation))
          @bounds.add(trk.bounds) if get_bounds
          @distance += trk.distance
       end
@@ -236,7 +235,7 @@ module GPX
          waypoints.each { |w| gpx_elem << w.to_xml } unless waypoints.nil?
          routes.each    { |r| gpx_elem << r.to_xml } unless routes.nil?
 
-         doc.save(filename, true)
+         doc.save(filename, :indent => true)
       end
 
       private 
diff --git a/tests/gpx_file_test.rb b/tests/gpx_file_test.rb
index 0f7f542..a604b11 100644
--- a/tests/gpx_file_test.rb
+++ b/tests/gpx_file_test.rb
@@ -4,6 +4,7 @@ require File.dirname(__FILE__) + '/../lib/gpx'
 class GPXFileTest < Test::Unit::TestCase
 
   ONE_TRACK_FILE = File.join(File.dirname(__FILE__), "gpx_files/one_track.gpx")
+  WITH_OR_WITHOUT_ELEV_FILE = File.join(File.dirname(__FILE__), "gpx_files/with_or_without_elev.gpx")
   BIG_FILE = File.join(File.dirname(__FILE__), "gpx_files/big.gpx")
 
   def test_load_data_from_string
@@ -38,4 +39,10 @@ class GPXFileTest < Test::Unit::TestCase
 	assert_equal(7968, gpx_file.tracks.first.points.size)
   end
 
+  def test_with_or_with_elev
+    gpx_file = GPX::GPXFile.new(:gpx_file => WITH_OR_WITHOUT_ELEV_FILE)
+	assert_equal(2, gpx_file.tracks.size)
+	#assert_equal(7968, gpx_file.tracks.first.points.size)
+  end
+
 end
diff --git a/tests/gpx_files/with_or_without_elev.gpx b/tests/gpx_files/with_or_without_elev.gpx
new file mode 100644
index 0000000..ce516a4
--- /dev/null
+++ b/tests/gpx_files/with_or_without_elev.gpx
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
+<gpx xmlns="http://www.topografix.com/GPX/1/1" creator="MapSource 6.5" version="1.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
+
+  <metadata>
+    <link href="http://www.garmin.com">
+      <text>Garmin International</text>
+    </link>
+    <time>2007-04-16T18:11:47Z</time>
+    <bounds maxlat="40.207429" maxlon="116.670578" minlat="39.876895" minlon="101.636217"/>
+  </metadata>
+
+  <trk>
+    <name>ACTIVE LOG</name>
+    <trkseg>
+      <trkpt lat="40.079434" lon="116.295948">
+        <ele>50.606567</ele>
+        <time>2007-03-25T05:17:34Z</time>
+      </trkpt>
+    </trkseg>
+  </trk>
+
+  <trk>
+    <name>LINE-13</name>
+    <trkseg>
+      <trkpt lat="39.949744" lon="116.427398"/>
+    </trkseg>
+  </trk>
+
+</gpx>