|Hey, thanks for your interest in the lib. You're almost certainly running into an issue with an outdated PHP version. dump_r requires PHP >= 5.3.|
Even though it would be fairly easy to make it run in older versions, I have no plans to support or back-port it to 5.2 because 5.3 was released well over 3 years ago. http://www.php.net/ChangeLog-5.php#5.3.0 and the current version is 5.4 as of 8 months ago.
If your host does not offer PHP 5.3 yet, I highly recommend that you find a provider that isn't stuck in the dinosaur era :D