All JDK 6 x64 bundles should be named using x64 instead of amd64.

Now names are like:
jdkfb-6u24-windows-amd64.exe
jrefb-6u24-windows-amd64.exe

should be
jdkfb-6u24-windows-x64.exe
jrefb-6u24-windows-x64.exe

See http://www.oracle.com/technetwork/java/javase/downloads/index.html
as an example