HDMI to VGA converter with Mac mini
The recommended way is to use the Thunderbolt (Mini DisplayPort) to VGA converter.

http://store.apple.com/us/product/MB572Z/B/mini-displayport-to-vga-adapter?mco=MTA4NDU0NjA

The Apple HDMI does not supply signal to VGA monitors.

The Cable you have is good, but only for Digital monitors and VGA is Analog type. OK if you are sufficiently confused now, just get the Mini DisplayPort to VGA Adapter and it will work.