It is possible that movements.org/Alliance for Youth Movements is a subsidiary organization covered under a group return filed by a parent organization (fiscal sponsorship), and that's why their 990 isn't coming up on Guidestar or Foundation Center.
However, according to the Internal Revenue Service, tax-exempt organizations must make available for public inspection certain annual returns and applications for exemption, and must provide copies of such returns and applications to individuals who request them. You can also request the 990 directly from the IRS. Additional information on the process is available on the IRS website at http://1.usa.gov/4F8MI7.
You can contact the organization for clarification on their name and tax-exempt status at info@movements.org
