Jay - there was this paragraph near the bottom of the page:
What About Me? According to the 2000 data, though the entire list of 151,671 surnames covers about 90 percent of the population, it accounts for only about 3 percent of surnames in the United States! The 2000 census found over 6 million surnames total, the vast majority (about 65%) held by just one person. So don't be discouraged if you're not on the list. Ninety-seven percent of all surnames in the United States didn't make the list.
I believe you fall into the 97% mentioned above. I have several friends (with Scandinavian last names) that are not found either.
Also - surnames tend to be spelled differently by different people. If you search "whitecloud" (one word) you get:
In 1990, whitecloud was ranked #59158.
In 2000, whitecloud was ranked #128766.