Immigration Site

Hi, I have submitted DS-230 with all the required civil documents and their photo copies for my mom, received by NVC on Nov 29th 2010. Today there auto mated service saying that the application is incomplete and they have send a letter about it. My question is
1.What could be missing as i have submitted what ever they have asked on their web site?
2.who will receive the letter for any missing document my mom in her home country or me as an agent and petitioner.
3. I have also submitted DS 230 with civil documents for my father but no update on that though i have submitted both packages together?
I hope i have not made any mistake.
thanks in advance