The Iron Horse Warrior Race model is a 27-speed hard-tail mountain bike with a Aluminium (Alloy 6061) frame and 26" wheels. This model was released in 2005.
When I try to take the rear tire off, it feels like it is stuck on. No matter how much I loosen the bolt, the axle won't come free from the frame.
The tire might be getting caught on the derailleur. Carefully push harder on the tire and try to force it off the bike. Take a look at the first few steps on this guide where the rear tire is removed.