I've never built a ringworld or sphereworld in SE5; the tech is far more expensive than in SE4, and games are likely to crash before reaching that point. But I have heard that there was an issue with the blocked hex radius for constructed worlds; it wasn't reduced when you switched to small systems, causing the vast majority of the system to be blocked off, even space outside the ringworld/sphereworld.

So the news turns out to be mixed. In sequential movement games, you can at least do a manual cargo transfer order ('T') to ring/sphereworlds when both objects appear in the sector panel but not a recover order. In simultaneous or when repeating orders in sequential, the transfer order will fail. Constructed items appear at (0, 0) and when they are located there, the orders will work. However due to the blocked radius of either the star (ringworlds) or the sphereworld itself, you can't re-enter the location.

If you set the blocked radius value of stars (or sphereworlds) to 0, then you can enter the (0, 0) location and the recovery/transfer functions work correctly.

I ended finding a discussion on the SE.net archived forum that covers most of this:
http://home.spaceempires.net/ftopict-9090-sphere.html

From my past experience, I've never had any issues picking up or dropping off cargo to these planets. What has never worked for me has been repeat orders. Let's say I have a sphere producing satellites...lots of them.. If I set up say a route from the planet to a worm hole with a satellite laying ship, If it's on the sphere planet and I start the route from there it will work fine until it returns to the planet, at the coordinates it started from, it will fail to pick up cargo at that point. If I do it manually, then I don't have the problem.

You need to colonise the ringworld/sphereworld after creation. Only then you can use it.
Took a while to find out....