This particular spin-off did not have an ex-dividend date. The shares were paid out to all holders who had settled positions on 4/29/2009.
Your sell trade did not settle until 5/01/2009, which entitled you to these spin-off shares.
Please reply to this message or contact our Reorganization and Safekeeping team Monday through Friday, from 9 a.m. to 5:30 p.m. ET (excluding market holidays) at 1-888-723-8504, option 1 if you have further inquiries.
Sincerely,
David Rischling Reorganization and Safekeeping, TD AMERITRADE Division of TD AMERITRADE, Inc.