I just joined, a year later... but I noticed this same problem. The instructions don't provide quite enough detail to necessarily get this right. It is left up to chance, with only 1/3 probability of getting it right on the first go.
Of the two horizontal drive shafts within the arm, the lower one is what controls the orientation of earth's tilted axis, so those are the parts that matter for this issue. What is required in step 203 for everything to work is that the axle orientations of both sides of that lower shaft match before joining up the two assemblies. Both ends of it involve a 12t bevel gear engaged with a 28t turntable, and this results in three possible axle orientations when everything is aligned: "x" (45 degrees), "+ tilted right" (15 degrees clockwise from vertical), or "+ tilted left" (15 degrees counterclockwise from vertical).
So to fix this after it has been assembled, you do need to reverse the last five steps to get back to the beginning of step 203. (Pull off one two-pin connector, pull off one 13L beam, pull off one 3x5 L beam, and partially push out two 3L pins, then separate everything.) When separating the two assemblies, be careful that gears don't fall out (especially the 12t bevel gear on the underside of the earth assembly), because the axle connectors may not pull apart the way we would like.
Once you have it apart (or once you reach step 203, if somehow you are reading this while building it from the beginning...), inspect the axle orientations of the lower shaft, while making sure the arm and the tilted earth axis are aligned as needed. It should be one of the three possible axle orientations on each side (either "x", "+ tilted right", "+ tilted left"). And if you had an alignment problem, then there will be a mismatch. The good news is that we can change these axle orientations without any further disassembly. Instead of disengaging gears and trying to reengage with certain teeth meshed (way too fiddly to do successfully), we can simply rotate a 28t turntable, one full rotation at a time, until the correct axle orientation is reached. The one inside the base is a bit more effort to manipulate, so let's consider that base/arm side fixed, and just manipulate within the earth assembly. You can grab onto the angled pieces immediately below the earth to turn it one full turn, which will turn the 28t turntable and the axle in question. Check the axle orientation again. It will cycle through the three possible orientations with each full turn of the turntable. So you may have to do it once, or you may have to do it twice, to reach the axle orientation that matches what is on the arm side. (And note that "+ tilted left" on the arm matches "+ tilted right" on the earth assembly, when looking at each face-on. And vice versa. And "x" matches "x", of course.)
Then complete assembly as usual. Sorry this was so long, I didn't have time to write a shorter version.
