I can tell right off that the exposure setting were not locked. Every frame has a different exposure. A real easy way is to set the camera to manual. Set the aperture to about F5 to F8 and set the shutter to about 1/125. Take a test shot. If its too dark go lower by 1 or 2 stops until you get a test shot with good detail in highlights. Use manual focus at infinity. AE_lock will do the same thing if you can set it up and remember to do it on each shot. If you use manual make sure to set the white balance to "direct sun" if you have a lot of natural light from windows. If you are in a room with no windows use incandescent or whatever is appropiate for the lighting.
Second because of the way the scene is lighted you should have been exposing at around 1/90. Looks like you exposed at about 1/250 or higher. The camera probably metered the windows and set an exposure based on this which will make the interior come out too dark. Spot meter the walls or a midtone area where the light is not too bright or too dark.
If you take a longer exposure or open the aperture up to F5 ish and you might find the exposre difference is much less. You would be making the overall frames much lighter or more exposed. This tends to lessen the exposure differences but they may stll be there but much less. This would make it possible to fix in photoshop without loosing quality in the shadows. The shadows contain much less detail than highlights.
Shoot for highligts and darken if necessary in photoshop. This way you can preserve more detail overall.
Also you might notice each of the 4 frames are nearly cetered on each window. Looking at your example imagine if the seams came across the windows therby splitting the light across 2 frames. This will help tremendously in minimizing these problems. In the future consider your seam placement in situations with multiple windows. Try starting the first shot in such a way that you move towards the windows then around to the shadow areas. Try not to point the lend directly at a window to start with.