First, make sure you have activated your CUIT ID at:

http://uni.columbia.edu/

Also, refer to the Library's FAQ on Connecting & Accessing Electronic Resources at:

http://www.columbia.edu/cu/lweb/services/faq/browse/eresources.html

Alternatively, the FAQ can also be reached via this path:

Columbia Homepage-->Libraries-->Help (top)-->Frequently Asked Questions (right)-->E-Resources Help

Report Electronic Resources problems here.