What kind of viburnum? Most are self-sterile, so they need a cross pollinator blooming at the same time to form berries.

dentata, there is another fairly small one within 100 feet.

Shadberry,

Cynthia's answer is correct but terse. I was going to expound on it, but found a thread that does a great job of giving the complicated botany and genetics that you need to understand. See the link.

I also realized in trying to justify my answer that I made a silly error in trying to get fruit on my Prague viburnum. (V x pragense) I bought a Prague from 2 different sources, thinking I would have 2 different clones that would be compatible for fruiting. Duh. All Prague viburnums are clones of the original V rhytidophyllum x V utile interspecies cross. Now I have to figure out what kind of viburnum I need - probably a true V. rhytidophyllum or maybe a seedling of V x pragense. Off to the shrubs forum for me...

Here is a link that might be useful: Viburnums pollination, propagation, provenance: Oh my!