Subscribe to topic from another language

We are testing Azure ServiceBus as a possible solution to integrate in to an existing infrastructure and require the ability to send and subscribe to topics from different languages.  During testing we are able to successfully send and receive messages with a couple of C# apps, but when replacing the subscriber with a php application using the azure php library we receive a 500 error message when attempting to retrieve  a message with the following code:

$options = new ReceiveMessageOptions();  
$options->setPeekLock(); 
$message = $serviceBusRestProxy->receiveSubscriptionMessage("TestTopic", "AllMessages", $options);

Should we be able to send messages between languages and how can we investigate the source of the 500 error message?

Cheers,

Matt