Part of the problem you're seeing is that WOAI and several other older freeware ai packages coded individual commuter airlines. This creates a problem when you're making an afcad for several commuters at one airport.
Example:
KDFW is served by American Eagle but is now also being served by Skywest and Expressjet. Years ago, you could have just coded EGF (American Eagle) the airport and been okay. But the world continues to turn and airlines change their commuter partners. Now you have EGF, SKW (Skywest), and ASA (Expressjet who merged with ASA (ASA) and are now both owned by Skywest but operating separately - confusing, right?).
To fix this, afcads have evolved too. Instead of listing each individual commuter, afcads now have and "X" added to designate commuter airlines. For example, any feeder for American (AAL) is designated "AALX." This allows the afcad to stay current no matter who is partnered with the mainline. Unfortunately, nobody has updated the older WOAI packages to reflect this.
You can fix this by editing the aircraft.cfg of your American Eagle ai. Change the line that says "atc_parking_codes=EGF" to "atc_parking_codes=AALX, EGF". That should fix your parking issue.