How to reference runtime prompt variables in a business rule

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I am trying to create a simple business rule that will run after saving a webform. Additionally, it needs to use the POV of the webform for some of dimensions. This is in order to reduce the impact of the rule and accelerate the execution of it (i.e. instead of running for all employees, it only runs for the employees that the user has selected/modified in his/her webform's POV)

I have created two runtime prompts for this RTP_Year and RTP_Employee as these are the two dimensions that could vary in my weform. Everything else has been put in a fix statement. I have referenced them as shown below using curly brackets { }, but I keep getting an error upon validating my rule.