Of the three, the only one that is very underexposed is "man", and to a lesser extent, "treat".
Capturing an image in an indoor room with a large light source like that window can be tricky because of the extremes in contrast. Your XTi's lack of a spot meter can make the task trickier. It appears that image is exposed more for the window and what's behind it than it is for the subject in front of it.
You probably could have used a slightly slower shutter speed for a more accurate exposure. You're shooting digital - you have nothing to lose by firing off two or three shots with different shutter speeds.
Also keep in mind that you do not have to frame your subject first. You can set your exposure on an area that's lit similarly to what you want to have exposed properly when you take the shot - in this case, the boys face. There's a couple ways to do this, one of which is locking your exposure (which I can't recall how to do offhand since I rearely use that feature on my XTi). But if you're comfortable with focusing manually, you can aim at a darker area of the scene, like between the two chairs on the left, press your shutter button half way to set you exposure, re-frame your subject and fine tune your focus, then press the shutter all the way to capture the shot. You would have been more likely to get the proper exposure on the first try that way, since you'd be exposing for the same lighting conditions as your subject.
With a few tweaks, you could have had the proper exposure there. Worst case scenario, the ship behind the window may have had to be a touch overexposed to properly expose the boy, but that wasn't your focal point in that image anyway. It's not the fault of the camera or the lens.
If you shooting a scene witth high contrast (very dark and very bright lighting in the same scene) try to expose on something "in the middle", meaning an area that's not too bright or dark.