Theatrepalooza said roughly what I was going to say. In community theatre (and theatre in general) there is a lot of politics to deal with. As director you need to have the final decision as to what you need to present your vision for the show. This should apply to your choices for all of the departments. However, if you are new to that community, you may want to have a listen to what the board has to say. They may know things that you don't know about specific actors. On the other hand there may be things that you know based on experiences with various actors that they don't know. If there are artistic differences of opinion then the final decision should be yours. So listen to what they have to say. Tell them their input was very interesting, and tell them when you will deliver YOUR cast list. If that is unacceptable, perhaps they picked the wrong director. There are multiple ways to look at this.