I just spent the weekend fighting with installing JBuilder 2007. When the installer would say something would take 5 minutes – it took 90. And the installation would usually end up failing. I figured out that in my case my antivirus package (F-Prot) was the culprit. Excluding the JBuilder installation directory from virus scanner fixed the problem. In my experience I’ve found that Java software and build tools are frequently troubled by antivirus software.
So, if you’re having slow installations or installations that are failing outright, try turning off your AV software for a little while.