"Buildism warning: This game is using an unsupported scripting technique..."

[Jacob__mybb_import1]

"...That will soon be removed, please notify the creator that <Text is cut off by in game window size>"

Which scripting technique is this referring to?

Using sleep() for a period of time longer than 0.5 seconds in an event handler. It will give you a more detailed message in edit mode (if it's your game, of course.)