Immigration Site

I posted this in the September filers, but I think I should post here because I have some trouble with my filing AOS.
Today I came home so that I can see the RFE request from USCIS. My dad received it a couple days ago. Actually, my RFE letter states:
"Form I-864 Affidavit of Support was submitted; however, it was not submitted from the petitioner/sponsor. In order to process your application further, submit a completed and signed Form I-864 for the petitioner/sponsor listed on form I-130 or form I-129F.
For more specific information, see Form I-864 instructions, page 2, ...."

I sent my I-864 along with other forms. Since Im the petitioner and having no income (still in college), my wifes uncle is her sponsor. Why do we get this letter? I dont really understand. Does this mean that her uncle has to mail the I-864 form separately from us? Anyone who knows anything about this, please help.

I got an answer from Thomas saying that I do need to file form I-864 even though my income is very little ($3000 a year).

Now Im filling out form I-864, but Im stuck on question 24b) which says "Income you are using from any other person who was counted in your household size, including, in certain conditions, the intending immigrant. Please indicate name, relationship and income"
Since my wifes uncle is our joint sponsor, do I need to put his name here? However, he is not in our household, and his I-864 was mailed to USCIS already.
Any help is greatly appreciated.

I sent my I-864 along with other forms. Since Im the petitioner and having no income (still in college), my wifes uncle is her sponsor. Why do we get this letter? You are the petitioner - hence, you are the sponsor. Your wifes uncle is her co-sponsor. There must be a I-864 from you in the packet.