Are you using it within Reaper, Tony?

I tried what you are doing here, loaded a midi supertrack and then added the CollaB3 VSTi on that track.

CollaB3 then displays the message "The buffer size 442 is not supported, use a multiple of 8"

I assume it is talking about a Reaper setting someplace, do you know? Never seen that message before, but then I don't do much with midi either.