Oct 21 (Reuters) - A new poll on Tuesday showed Ebola ranks well behind the economy, jobs and other issues among America's top problems, while a law enforcement official warned about Ebola-related scams promising protection against the virus that has killed thousands in West Africa. Ebola debuted in the top 10 concerns of Americans but remained far behind five other issues: the economy, dissatisfaction with government, jobs, healthcare and immigration, the Gallup polling organization said.