Apple’s iPhoto:System Failure Error while sending photo

Hi,
Has anyone had any success with ePrint, when email is sent from within Apple's iPhoto?
I have a Photosmart Plus, B209 model. Printer Status in HP ePrint center is ready & connected.
Sending email with photo attached from the gmail web interface, works as expected.
Sending the same photo, from within iPhoto using the "Share via email" function and using the same Gmail account, results in job failure with the remarkably unhelpful error, "system failure" reported on the Job Status screen, in the ePrint center.
Any suggestions or any known issues would be appreciated. Search of forum doesn't show any threads referencing iPhoto specifically, although some reporting issues with various mail clients are not working.
I hope I've come to the right place with my issue.
Thanks.
