[PvK]

Ya, both situations are Proportions changes. If you don't get any technology, it is often because the suspicion of ancient technology turned out to be false or not useful enough to give any advances. This is intentional - Proportions greatly increases the number of possible ancient technology sites shown, but most of them don't give anything - you have to actually go claim it to find out. This also happens, even in the default game, if the ruins contained only technology that you already had developed.

The second case, where it says something was found, but you can't build it, is because you have to research it first. This is for realism's sake - if an ancient shield disruptor suddenly appeared in Los Angeles, even if it came with a manual, it'd be quite a while before we even knew what the heck it was. The ancient massive items are all like this in Proportions. They all have to be researched, and have several levels of development, leading to some rather powerful (if also expensive and perhaps overkill) items.

PvK