Teleporter/Border trigger malfunction

I'm not sure how to categorize this particular meddlesome. I am constantly running into walls, but after I work on it a bit I usually figure out how the editor operates and how to use it. But I just recently put in a teleporter grouped in the Terrain, from the instructions of core academy, and I just can't figure out how to make it work.

I followed the instructions, and at first it was rough. Even with the spawn point, with the teleporter in the middle, it forced spawn my character at the teleporter, which made him constantly fall through the ground. In the Core academy it told me to 'find' the target field, but other than that I was on my own. So i fiddled it and edited 'Target' to 'spawn_point' or 'core_object_reference' (when hovered over target, it told me to type this) to see if i would get a different result, but I edited 'Target' to 'spawn_point'.

With this in tow, when testing the game to see if I get teleported back into the game after leaving the restricted area I created with Trigger under Teleportation, I simply just fall off the edge, and nothing happens. When leaving the test play, I am welcomed with the message 'Error running Lua task: [6A939C382F7549DA] TeleporterServer:23: attempt to index a nil value'. And have absolutely no idea what that even means, but assume that something in the teleport properties is off. However I have failed to see what it could be after sifting through all the teleport properties.

My apologies if it's a lot to read, but wanted to lay out one of the problems I've run into. Any help is appreciated, and more so if you reply in detail of thoughts, feedback and concerns.