Sounds like a problem with the installation.
What could go wrong with an installation on a Windows machine that uses the binaries? Why would it be only these functions (that I can tell) that would be missing? Is there somewhere I can go and check (possibly using phpinfo()) to find out if these functions should be available?
basename() works, dirname() works, filetype() works... all functions seemingly similar enough to, at least in my mind, filesize() such that I would think that if filesize() is undefined then those other functions would be undefined too.
thnx,
Chris