Ubuntu 7.04, upgrade "NOT AUTHENTICATED". What should one do?

[Rick Berger]

I just got notification that 'tzdata' has an upgrade but when I went to
install it, the update manager says it's not authenticated and warns me
of possible installation consequences. Is there a nice easy way to
verify if this could be an error? Is the a web site on what upgrades
went out when? Should it be reported, if so where? What should one do?  

Rick