Affidavit of support is not required for DV Immigration.
pls goto the following link.
http://travel.state.gov/visa/immigrants/info/info_3183.html#_Overview_–_Who
Who Needs an Affidavit of Support?
This form is legally required for many family-based and some employment based immigrants to show they have adequate means of support, when planning to immigrate to the U.S. Generally, the following intending immigrants need an Affidavit of Support:
i. Applicants for family-based immigrant visas, including certain orphans.
ii. Applicants for employment-based immigrant visas where a relative filed the immigrant visa petition or has a 5 percent or greater ownership interest in the business that filed the petition