MASS is blocked for R 2.15.0

I updated R to R 2.15.0 via apt-get and received the message that 
r-cran-mass was blocked.
I recently tried apt-get update/ apt-get safe-upgrade and received the 
same message, for
r-cran-mass-7.3.16-1lucid0

I currently have MASS 7.3-7 installed

How can I figure out what is wrong and correct it?

thx,

Michael Friendly     Email: friendly at yorku.ca
Professor, Psychology Dept.
York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street    http://datavis.ca
Toronto, ONT  M3J 1P3 CANADA