When I try to install Sun JDK 1.6.1 on Windows XP I get the following error. Error 1721. There is a problem with this Windows Installer package. A program required for this install to complete could not be run. Contact your support personnel or package vendor. What do I do?

The java website posts this as a known problem and has a few solutions.

Hope this helps: Error 1721: There is a problem with this Windows Installer Package (http://www.java.com/en/download/help/error_1721.xml)