I would try again. The published rules only prohibit upgrading with miles on fareclasses I, O and Q (on certain routes). They are capacity controlled and it could be a coincidence that there is no upgrade eligible inventory on your flights. Another possibility is that the agency has used an "unpublished" S-class fare.

Upgrade awards are only valid on individual published-fare tickets and are subject to capacity controls.
The following fares are not upgradeable:
Fares booked in I or O
Fares booked in Q between North America and Asia, Europe, India or South America.


http://www.aa.com/apps/AAdvantage/Vi...t#travelawards