I tried setting a splitter up as shown in your gifcat and the server crashed with this error message: Error while running the event handler: compoundsplitters/control.lua:245: attempt to index local 'buffer' (a nil value).

Imgur link: http://i.imgur.com/rhAtuTL.png, you can see the attempt in the background.

the same happened to me. its attempting to find a totem on the buffer side, but factorio states there is no "buffer" item.

Fix In route- thanks for the bug report.

Still getting issues creating a splitter:
787.894 Error MainLoop.cpp:603: Exception at tick 29982: Error while running the event handler: compoundsplitters/control.lua:245: attempt to index local 'buffer' (a nil value)

@innomin8 that's an old error fixed by 0.2.5

Error still exists... occours only when placing the end cap last after placing a blue or green before..

fix for error on control.lua:338 put into 0.2.7