You should be able to trash caches manually. I don't know if this is the same in 10.4, but in 10.6 go to ~/Library/Caches and delete com.Apple.Safari. If you don't find that folder, try the contents of ~/Library/Safari and look for caches (I seem to remember that that's where they were stored in 10.4 but I can't be sure).
In addition, you can delete Safari caches by going to the Safari menu and clicking Empty Cache or by pressing Command-Option-E.