Rider of the ARPocalypse
I know it's off topic, but folks here tend to know more of the technical side of things. Can't play this with a MIDI keyboard (get that error). Can use it with a MIDI interface and can play it, but it will crash to that error after. e.g. you stop the recording on the DAW. (Using Cakewalk) this happens with two different interfaces (Behringer Uphoria and M-Audio Audiophile) and two different versions of Cakewalk (WinXP and Cakewalk 9, and Win10 and the latest from Bandlab) as well as Rosegarden.