There are two issues which may cause these errors with a design.
The first is that in order to use an Output on the right hand side of a supervisory equation it must also be assigned a value somewhere in the design. It could be assigned in a step of the Sequence or in the Supervisory equations. But you must assign the output to a level within your design somewhere if it will also be used on the right hand side of a supervisory equation.
The second issue is that it is not possible to use an output in your logic when that output is set from the I2C bus. This won't work because the feedback from the output back into the PLD logic array occurs before the output switching occurs. See figure 2-10 in the POWR1014/A data sheet for a diagram of the PLD architecture and figure 2-13 for the Digital Output Pin Configuration. When the digital output is configured for I2C control the feedback signal is not connected to the actual output any longer. The only way to have internal logic that is controlled by an I2C register value is to use an input that is controlled by I2C.
Please see the POWR1014/A data sheet for more information: Power Manager II POWR1014/A data sheet