I had to send in my test THREE times and my ancestry was finally determined to be 70% central european, 23% British Isles, and 7% unknown.
I doubt that it has anything to do with African-American ancestry. My husband's results came back immediately, 88% British Isles, 7% southern european and 5% unknown (and we though since his father was Puerto Rican, that he could possibly have some African blood.
I was most concerned with my 90 year old aunt's autosomal DNA test. Her results came back within 10 days of beginning processing.