For anyone else who has a StamPLC and a StamPLC AC Relay and is having issues using the UIFLOW2 AC Relay Blockly module and getting errors. The below screenshot shows how to use the I2C module to get it working. I used the https://www.diodes.com/datasheet/download/PI4IOE5V6408.pdf datasheet to work out which registers need to be set up to get this working. Keep in mind the LED's work on an opposite logic level to the relay.
After Some Tinkering I have a working example for anyone else who needs it. 
I did try to share this on the project zone but like most things on here it throws errors instead of just working...