By John S. McClenahen Compared with last year, the percentage of CEOs in the Americas, Europe, and Asia viewing the Internet as a major market challenge has more than doubled, to 38% from 15% reveals a survey of 506 CEOs conducted by Accenture LLP, formerly Andersen Consulting, and the Conference Board, a New York-based business research group. Thee surveyed chief executives are in manufacturing, manufacturing-related services, and other service industries. However, a big gap seems to exist between CEO concern and the impact the 'Net is having so far on their businesses. Only 25% of the CEOs recently surveyed by PricewaterhouseCoopers LLP, New York, report that e-business "completely reshaped" or "significantly impacted" their companies last year. A majority, 53%, views the 'Net as having little impact -- and 22% say e-business had no impact at all. Some 871 CEOs in the Americas, Europe, and Asia participated in the PricewaterhouseCoopers survey of manufacturers and service providers. Among manufacturers -- as among companies generally -- a majority of CEOs (54.2%) believes that electronic business had little impact on their companies in 2000. Nearly 28% claim there was no impact at all -- while a surprisingly low 17.7% relate that e-business "completely reshaped" or "significantly impacted" their companies last year.