this happens when 1. if java already exists or 2. when you have uninstalled it incorrectly previously thus what you do is that use CCleaner and delete the entry from the registered product list in Tools->Uninstall
pm me if u have more doubts
Solution to Java Installation:
I found a utility on majorgeeks.com Java Ra
It will uninstall the previous version of Java and allow you to install the newest version.