What I would suggest to do is go here
and download all the packages for Mozilla 1.3 into one directory. Then do:
rpm -Uvh mozilla*
and it should update you to Mozilla 1.3 . It seems that the update agent keeps the old Mozilla directories around for some reason. What I did was first remove all of the older Mozilla rpm packages, remove there directories, and then install the new Mozilla rpms. That way there is no trace of Mozilla 1.1 .