Repair permissions. If no go, check http://h10025.www1.hp.com/ewfrf/wc/softwareCategory?os=219&lc=en&cc=us&dlc=en&sw _lang=&product=3793676#N182 and download the latest HP stuff, install it, and run the Software Update again or manually download and install the 2.5.2 update.
That I can't answer, but that model does appear to have been out for some time. Peruse the first link I sent and you'll see it states support for Tiger and Leopard under the specs or requirements link. Maybe another call to HP support or an e-mail through channels: http://h20180.www2.hp.com/apps/Nav?hpagetype=s-005&h_cc=us&h_lang=en&h_page=hpcom&h_product=top&hclient=test