Error in applescript "Invalid index"
The values you set before are not given via the inputparameter. As long as you run your Automator Workflow as an Automator Workflow and not as an Application or Service, you can access your formerly set variables using the following:

tell application "Automator"
    set cat to value of variable "NameOfFirstVariable" of front workflow
    set x to value of variable "NameOfSecondVariable" of front workflow
    set o to value of variable "NameOfThirdVariable" of front workflow
end tell


inside your "Run Applescript" action.

Greetings, Michael / Hamburg