Windows, Finale 2011, Kontakt 5, Writescore Template

Why am I getting vibe sounds when entering in the marimba staff, and marimba sounds while in the timpani staff?

My guess is that you probably have the wrong KP banks/channels assigned to the your score staves.  Check the Instrument List against your KP assignments.  If that isn't it, we'll have to look further.

That was it.  Thank you.