The 11g XE 32-bit version is not certified on 64-bit Windows - that means the software has not been officially tested on a 64-bit platform - the install may or may not succeed - if the install succeeds, the software may or may not work as advertised. Any issues arising out of using this uncertified combination, you will have to troubleshoot on your own.
I'm just curious, if this is the case why won't a 32 bit database program work on a 64 bit OS?
Probably things are not so simple... anyway, apart from the reason why it won't work, did you see Oracle Database Express Edition 11g Release 2 Downloads ?
There you can read : Does not work in Windows x64 : isn't that sufficient ?
See my detailed answer about what you will encounter if you try to install on 64-bit windows in the following thread (fourth response):
That thread has had over 500 views and so far, no one has offered a solution for the errors I encountered when testing.
Depending on your needs, you could install the Express edition in a 32-bit windows virtual machine (I like virtual box for small test instances) or Oracle offers a developer license for 64-bit versions of their database software.