Reading from Google Spreadsheets with RGoogleDocs

I cannot read google spreadsheets. I get the following error:

assignment of an object of class "NULL" is not valid for slot "access"
in an object of class "GoogleSpreadsheet"; is(value, "character") is
not TRUE

RGoogleDocs is on the cusp of brilliance. How can I troubleshoot this
apparently last remaining problem?

Farrel J. Buchinsky, MD
Director, Respiratory Papillomatosis Program
Allegheny-Singer Research Institute
320 E. North Avenue
Pittsburgh, PA 15212-4772