Question
I have tried to use the updated Airbus gauges for FS2004, but FS doesn't want to load them.

Answer
Just like for FS2002, you must declare the FSSOUND module as an old module. Edit your fs9.cfg file and add the following lines:
FIND THAT HERE:
http://forums.avsim.net/dcboard.php?az=show_topic&forum=121&topic_id=129218&mesg_id=129218&page=

[OldModules]
FSSound.dll=1