See if this helps.
http://www.gnutellaforums.com/showpo...00&postcount=7

Make sure to use the offline installer (not the recommended one)...less chance of installation problems
Install Java first, use the offline JRE installer & remove your previous Java version before installing the new one.
http://java.sun.com/javase/downloads/index.jsp

If you're still having trouble, try using the 'other' installer.
Installing using the 'other' installer