[ic] logging in but [data session username] not set.

[Cameron]

I noticed in the past that someone else has had problems with this, and
there didn't appear to be any resolution for them either - when i create a
new account and log in, everything works fine, but if i close the browser
and go to log in to that account again, it doesn't work. The error log shows
that the login succeeded, mv_username has the right username in it,but [data
session username] is blank. I assume that [if session logged_in] works on
checking whether [data session username] is set, yes? The docs state quite
specifically that when you log in succesfully (which apparently i'm doing if
the logs are correct) then the session username variable gets set. I am
using a direct copy of the foundation login.html page to log in...