You could try reinstalling Safari.
You can download Safari 5.7.1 from here:
If that is not the version you need, you can google for the specific version you are running.
I do not think that there is a modern browser available for 10.3.
You could try http://www.icab.de/dl.php
If you're using MacOSX 10.3.9 - 10.4.11, the 32 Bit version of iCab 4.9 is the recommended release for your system.