Point releases are built for 32-bit Windows, and may have problems running on 64-bit versions. Please post on the FreeOrion forums if you have experience running on 64-bit OS's. 64-bit Vista might have problems, however.
I'm running Windows XP Pro x64. FreeOrion installs and runs fine. There is just a minor issue with idle AI players. Python 2.5 doesn't seem to work. After installing Python 2.6 and replacing the python25.dll in the fO root folder with a python26.dll(renamed to python25.dll) everything works as it should. My guess is, that Python 2.6 has better 64 bit support.