sounds really strange that your board is not having the bootloader. I would first try to install the drivers to the board from FTDI using the executable from their website. Sometimes, Windows Vista under some computers, brings problems due to specific OEM drivers put in your machine by the computer manufacturer.
Try to get the file at:
http://www.ftdichip.com/Drivers/CDM/CDM20600.exe
which is an installer compatible for all sorts of Windows machines, it will whipe off previous versions of the drivers. If things are still not working after that, then you should consider your board is having no Bootloader. The best way to check that out is by pressing the reset button. If the LED by pin 13 is not blinking quickly every time you press it, then there is no Bootloader.
/d