I was able to download Facebook w/o any issues-I tried downloading AIM and Google Talk laterr in an area with poor coverage and had to click download multiple times before finally being able to load the page. Could be your issue.
Are you downloading facebook by going to the mobile facebook site, app world or mobile blackberry site? I'm not sure if the link on the mobile facebook site is still working, if you are unable to use the app world go to mobile.blackberry.com and you should see the link right away for the facebook 1.6
If you transfer your setting from your previous blackberry like I did, I had to tell app world to uninstall facebook and then reinstall it so the icon would show on my tour.
