According to an article about data warehousing, the primary causes of failure are not associated with the technology, problems with the data model, problems with storage or operating the data warehouse.  Instead, these authors found the primary problems associated with failure include political and organizational problems.  In order, they found the following contributed to the failure of data warehousing projects.

•  Inadequate user involvement
•  Insufficient funding
•  Organizational politics         
•  Weak sponsorship and/or management support   
•  Wrong or poorly analyzed project scope    
•  Data problems        
•  Problems with end-user access tools         
•  Poor choice of technology
•  Scope creep           
•  Turnover of organizational personnel

Watson, H., J. Gerard, L. Gonzalez, M. Haywood, and D. Fenton. “Data Warehousing Failures: Case Studies and Findings,” Journal of Data Warehousing, 4(1), 1999, p. 44-55.