Domestically in the US, a DONEn books into A (first) on 2-class flights, D (business) on 3-class flights, and Y (economy) on single class flights.

If there is no availability in A on a 2-class or D on a 3-class then you can get L (economy) if available.

Why are you using a travel agent with no expertise in these tickets? I would recommend setting them up through the AA RTW desk.