The System.Type type cannot be serialized like that. You could add a string property, like this:

[DataContract]
public class Frame
{
    [DataMember]
    public string FrameName { get; set; }

    [DataMember]
    public string FrameTypeName
    {
        get
        {
            // or FrameType.FullName, depends on compatibility between client & server
            return FrameType != null ? FrameType.AssemblyQualifiedName : null;
        }
        set
        {
            FrameType = value != null ? Type.GetType(value, true) : null;
        }
    }

    // don't serialize this one
    [IgnoreDataMember]
    public Type FrameType { get; set; }
}