数据库保存的外键约束

我目前收到此错误消息：

INSERT 语句与 FOREIGN KEY 约束“FK_ViewDocumentAudit_UploadedDocuments”冲突。冲突发生在数据库“Butler”、表“dbo.UploadedDocuments”、“Id”列中。该语句已终止。

这是我的实体模型 -UserId和DocumentId都是外键：

public partial class ViewDocumentAudit
{
    public long Id { get; set; }
    public long UserId { get; set; }
    public int DocumentId { get; set; }
    public System.DateTime DateAccessed { get; set; }

    public virtual UploadedDocument UploadedDocument { get; set; }
    public virtual user user { get; set; }
}

这是我在数据库中插入一条新记录：

public static void ViewDocumentAudit(long userId, int parsedDocumentId)
{
    using (Entities dbContext = new Entities())
    {
         ViewDocumentAudit auditObject = new ViewDocumentAudit();
         auditObject.UserId = userId;
         auditObject.DocumentId = parsedDocumentId;
         auditObject.DateAccessed = DateTime.Now;

         dbContext.ViewDocumentAudits.Add(auditObject);
         dbContext.SaveChanges();
     }
}