I just upgraded to v188.8.131.52 because I was experiencing increased crashing of Firefox when visiting sites which had a lot of Flash or other activity. Now the Page Up/Page Down function on my keyboard does not work with Firefox. I was running OS X 10.4.3 and repaired permissions; restarted; then upgraded all of the Macintosh update software, including the 10.4.7 update. Repaired permissions again, and it still doesn't work. Am I missing something in the Preferences Panel which was turned off. Thanks for your help. I have a 21" monitor and I'll go crazy if I can't use the Page Up/Page Down when browsing.