A trader yells on the floor of the New York Stock Exchange in New York City. - 

After a week of near-record highs, Wall Street appears worried again -- one of the culprits may be new concerns about the European debt crisis, especially over issues in Spain or Greece.

In Spain, there are worries about a corruption scandal that may threaten the government.

"There are still fundamental problems in some of these countries," says Julia Coronado, chief economist with the investment bank BNP Paribas. "Spain is in a tough spot. The economy is in terrible shape, people are suffering. If there is a sense that the government isn't contributing their fair share to the pain -- that threatens the stability of the agreements that have been reached."

Follow Jeremy Hobson at @jeremyhobson