graphviz-php - segmentation fault

I am on RHE 6, I have installed the latest rpms with yum:
graphviz-2.34.0-1.el6.x86_64.rpm
graphviz-php-2.34.0-1.el6.x86_64.rpm

I can run the example on the command line (/usr/share/graphviz/demo/modgraph.php) successfully.

I am trying to produce a simple graph with a php page on Apache (2.2.15) using the following code:
<?php
include("gv.php");

$g = gv::digraph('my first graph');
$node1 = gv::node($g, 'node1');
$node2 = gv::node($g, 'node2');
$edge = gv::edge($node1, $node2);
$edge = gv::edge($node1, $node1);
$edge = gv::edge($node2, $node2);
$e = gv::edge($node1, '11');
$e = gv::edge('22', $node2);
$e = gv::edge($g, 'x', 'y');
$e = gv::edge($g, 'x', 'y');

$f = fopen('output.log', 'w') or die("can't open file");
fwrite($f, (string)time() . "\n");

fwrite($f, "layout\n");
$r = gv::layout($g, 'dot') or die('layout error');
fwrite($f, "$r\n");

fwrite($f, "render\n");
header('Content-Type: image/png');
$r = gv::render($g, 'png'/*, 'graph.png'*/) or die('render error');
fwrite($f, "$r\n");

fwrite($f, "remove\n");
$r = gv::rm($g);
fwrite($f, "$r\n");

fclose($f);
?>
The resulting output.log looks like this:
1387402262
layout

The browser (Chrome) shows "No data received" and the Apache logs show:
[Wed Dec 18 14:37:27 2013] [notice] child pid 12145 exit signal Segmentation fault (11)

I tried using an earlier version of the rpm (2.26.0-10.el6) and at that point I do not get a Segmentation fault in Apache logs and the output.log looks much better:
1387404734
layout
1
render
1
remove
1

but Chrome still doesn't show anything at this point, the error message is (to me) cryptic:
Error in event handler for (unknown): TypeError: Cannot read property 'className' of null
at chrome-extension://kcnhkahnjcbndmmehfkdnkjomaanaooo/contentscript.js:111:162
at extensions::messaging:327:9
at Function.target.(anonymous function) (extensions::SafeBuiltins:19:14)
at Event.dispatchToListener (extensions::event_bindings:386:22)
at Event.dispatch_ (extensions::event_bindings:371:27)
at Event.dispatch (extensions::event_bindings:392:17)
at dispatchOnMessage (extensions::messaging:294:22)

Is graphviz-php still supported? Is there more code I could look at? Did I miss something? (rpms? typo?)

See

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