I had the same issue, and ended up downloading it directly from here:
http://www.launcherpro.com/apk/LauncherPro-0.8.2.apk
Once it downloaded, I could install it from the pull-down notifications bar on my Droid 2.
In my case, I had my phone set to not allow installation of apps from sources other than the android market, so I was (luckily) bumped to "settings", which i was unable to access before. I uninstalled the old version of launcher pro, enabled installation of apps not from the market, and reinstalled the new version of launcher pro. I had to reorganize the icon layout on my home screens, but my phone otherwise works fine now. So it was a little clumsy, but worth it.