@Jeroensy last time i gave the answer as "Fixed" is not used that often out in the field therefore is easily forgotten or simply not known.
For this question please allow me to help you by explaining what the question means .Fair ?
"Update these lines items to reference the driver in EMP03"
lets break it down
"Update these line items"
What line items ? I think the answer to this question is in the screen shot you attached Anaplan.JPG
How to update these line items
You need to calculate these line items by referencing drivers located somewhere . Also in Anaplan.JPG screenshot
What formula to use ?
Have a look the module you identified in above . What dimensions are being used ? how do these dimensions relate to the module where you have to write this formula ? Also look at the values in the module , these values are % . % makes sense when it is OF something . What could be the OF part of the % listed in this module
As far as your formula error goes
Error says line item is not valid . what does this mean ? how to fix this ?