Linux, Why can't I write even though I have group permissions?

Question

I want to create a file in a directory owned by the staff group which I am a member of. Why can I not do this?

bmccann@bmccann-htpc:~$ ls -l /usr/local/lib/R/
t         


        

Answer 1

Did you logout and log back in after making the group changes? See:
Super User answer involving touch permissions failure