I wouldn't consider complete graft failure so much of a problem as I would the suckering that grafted forms can often generate. V. carlesii is often grafted on either V. dentatum or V. lantana rootstock and both can generate a lot of suckers, which if left unchecked, could overwhelm the grafted shrub.

Carlesii is not the easiest of the viburnums to propagate, hence the tendency towards grafted forms. However, with some care it does strike from cuttings taken in early summer so nongrafted or own-rootstock plants are available.

Thanks---I completely overlooked the suckers. I know better. So, I spent the day on the phone calling all of the big (and some of the small) nurseries here trying to find it on it's own roots---no luck what-so-ever. I even called Hoogendoorn---who introduced Compactum---and even they sell it to their retailers as a grafted plant.

Not sure where to go from here.

A great many plants are grafted, often to a suckering root stock. Doesn't necessarily make them less desirable or even less robust. It is done primarily for ease of propagation but also often to provide the grafted plant (scion) with increased disease resistance and/or size limitation. Just be aware that suckering is a possibility and keep on top of it. You should be fine.