Can anyone give me advice in upgrading my Safari?

I am currently running Safari 1.2 on Mac OS X 10.3.9 - it keeps crashing when I navigate away from the apple site and I am keen to upgrade.

I tried using the normal software update with no result.

I tried downloading Safari 1.3.1 (which is supposed to be compatible with 10.3.9 - correct me if I'm wrong) but when it comes to choosing a volume to install the package on, the error message : 'You cannot install this software on this volume. This system cannot use this software'.

So I am stuck running a version of Safari that crashes most times I navigate away from the apple page and can not run things like BBC iPlayer or youtube.

Any help/advice would be much appreciated!