Can I have a co-signer on the 203k loan for the HUD GNND program w/o defaulting?

I recently won a bid through the HUD GNND program. Because the house needs work, I have to get a 203(k) loan; however, I am running into problems with getting the loan. I wanted to see if it is possible to have a co-signer on the loan without defaulting on the GNND guidelines, and still be eligible to get the house.