@@ -1514,16 +1514,22 @@ class DotWidget(gtk.DrawingArea):

     def run_filter(self, dotcode):

         if not self.filter:

             return dotcode

-        p = subprocess.Popen(

-            [self.filter, '-Txdot'],

-            stdin=subprocess.PIPE,

-            stdout=subprocess.PIPE,

-            stderr=subprocess.PIPE,

-            shell=False,

-            universal_newlines=True

-        )

-        xdotcode, error = p.communicate(dotcode)

-        sys.stderr.write(error)

+        try:

+            p = subprocess.Popen(

+                [self.filter, '-Txdot'],

+                stdin=subprocess.PIPE,

+                stdout=subprocess.PIPE,

+                stderr=subprocess.PIPE,

+                shell=False,

+                universal_newlines=True

+            )

+        except OSError as exc:

+            error = '%s: %s' % (self.filter, exc.strerror)

+            p = subprocess.CalledProcessError(exc.errno, self.filter, exc.strerror)

+        else:

+            xdotcode, error = p.communicate(dotcode)

+        error = error.rstrip()

+        sys.stderr.write(error + '\n')

         if p.returncode != 0:

             dialog = gtk.MessageDialog(type=gtk.MESSAGE_ERROR,

                                        message_format=error,