I'm not sure the reason for the hibernation file hiberfil.sys being enabled in a default Windows 2008 Server install, but use this to remove it:
powercfg.exe /hibernate off
If for some reason you need to put it back, use:
powercfg.exe /hibernate on
You need to use this command, as this setting is unavailable in the GUI. This also can apply to Windows 7 especially after a P2V.