On Vista/7/8 The default temp directory returned by winapi GetTempPath() is 
`C:\Users\%user%\AppData\Local\temp`. If user's name contains unicode 
characters then PHP won't be able to use this directory. In this case a 
different temp directory should be set. Check the following directories whether 
they exist and are writable, in this order:
  C:\Windows\Temp (or C:\%WinDir%\Temp)
  C:\Temp
  your application\temp
  C:\Users\Public\Temp
If these fail, try creating temp directory in the following locations:
  your application\temp
  C:\Users\Public\Temp