What OS are you installing on? Server 2008 requires some added tweaks.
Do you have maintenance windows setup? It will not install if it is in a maintenance window
I found that if I had everything set up correctly and it did not install, that I was impatient and I needed to give it a day to work itself out. Also did you check to see if it is installed from the task server itself? In my impatience I managed to confuse the system and had it installed on the task server but not showing on the SMP. There were manual uninstall instructions for the package server but my links are no longer good.