I'm using the following formula:

Select {CCE_WPX.Status}
    case “Active Injector” : “AI”
    case “Producing Oil Well” : “PO”
    case “Producing Gas Well” : “PG”
    Default : "VERIFY"

but get the following error message:

"A number, currency amount, boolean, date, time, date-time, or string is expected here.

I'm not sure where I'm going wrong as I have used this format previously.

Thanks.