If you havn't tried already, unzip the contents from the Firefox 1.5 download into a common directory such as /usr/lib. Each user should be able to access the program then. Although you will most likely have to create a link to the executable for each user on your system. This is what I've done and seems to work fine. You could also try using 10.1 or 10.2, both, I believe, come with Firefox 1.0.2 which can be patched to 1.0.7. Good luck.