The Glosa word for neighbor is para-pe, or para-fe or para-an if you want to be more specific. Beside-person? Beside what, and in what sense? To me, that sounds more like a co-worker or spouse, or the passenger next to me in a plane, if taken more literally.
Sometimes that's not a big problem, because once you learn that a purple-berry is your blackberry, and a wine-berry is your grape, you'll be okay. (Blackberry? Uh-oh. Yep, English has its problems too!) And once you've embraced the word, it can help you remember the component words. Speedwords' zofid for dog helps me remember zo (animal) and fid (faithful, loyal). But maybe that's a cultural thing, too. Are dogs considered faithful everywhere?
If the breaking down of a compound word into its components doesn't point directly at its meaning, if you have to learn the combinations as discrete entities, then 1) you've lost some of the utility of agglutination and 2) you might just as well have a separate word for the thing.
Makes me wonder if agglutination-type wordbuilding really works well between cultures that don't already have a lot in common. In the early stages anyway. Once you're familiar with it, any language can work. The question is, how long will it take to reach that point? And that's an important question for an International Auxiliary Language.