The reason why it is not working is because in the bounded RED area you have two commas which signals to AwareIM that you have three variable,
Income.Amount then a variable with $# then another variable containing ##0
You could try changing the $#,##0 to be $#.##0 and see if either the attribute format or the locale format takes care of it. Other than that - I'm stumped. In the past, to get round this I've used Total Amount: £<<SUM Income.Amount,0.00>> which kinda worked until I got a European customer who needed commas instead of full stops as the decimal separator. Fortunately they were very understanding.
Maybe this is one for Vladimir