Well that's not true, you don't need both 32 and 64 bit library.
You must check what java version you are using.
If you are using a 32bit version, then of course you need the gsk 32bit version. But if you ensure that EVERY component is 64bit, then you can install only the 64 one.
If you are not sure of all the component used, then of course you need to have always version in case you are using either 32 or 64 binaries.
Hope that help to clarify your issue and the issue of others.
Yours sincerely,
Alessandro