HP KVM Series EO1013, firmware update problems.

I am attemping to update the firmware on an HP KVM Series EO1013, P/N 336044-B21. As far as I know I need to make a serial connection then run the firmware update utility that I got from HP, but when I run the update utility it says no device found. I’m not very fimilar with serial, so does anyone have any tips or advice to how I could make this connection and update the firmware.