I can't unlock HTC Wildfire S bootloader.

[hack3rcon]

Hello.
I have a HTC Wildfire S and I like to unlock it for installing Cyanogenmod. I download the cyanogenmod and RUU for HTC and when RUU reboot my cellphone for unlock bookloader then it show me an error about "USB device unplugged", Why? What is my problem?

Thank you.

 

[hack3rcon]

Any idea?