no sound after sequencer start

hi, i got a sample mapped to an instrument and for input omni is selected.. everything is working fine.

but when i safe my project in the sequencer (no matter if cubase or ableton) and then load it again i see the midi notes in the instruments being played but dont hear any sound.

the only way to hear the sound is when i change the input from omni to default and then again back to omni. after that everything is fine again and i hear the sound (tho i actually didnt change anything, i only toggled and toggled back to omni)

as u can imagine this sux a lot when u got like 5-10 instruments loaded and have to to do this for all of them each time u load a project.. any thoughts what i might be doing wrong or is this a known bug?

edit: sorry this is the wrong area.. please move it to kontakt ^^