SAP Process Automation App - Launchpad Services Error

Hi,

I've developed a trial app in SAP Process Automation (based on the 'Special Projects' tutorial on Murali Shanmugham's excellent blog series) which runs as expected via the process URL. However when I set it up in Launchpad services and run the same process via the Process 'tile' I can input into the 1st form in the process but when I click 'Submit' I receive an error 'Process Instance creation Failed'. I've checked role access and all looks ok.

Thanks