No, sorry ,I meant to say that you have to be on stock RUU to be able to achieve s-off. The guide that I followed was "The HTC Superguide " in the development section of this device. Firstly, I did a full wipe, as in Dalvic cache, Cache, System, Boot and Factory Data Reset, also SD card, then I relocked the device with "fastboot oem lock", after that I tried to run the stock RUU ( The one the phone was originally on ), which started the initial flash but stopped at about 10% and came up with " ERROR 140 ". I tried 4 or 5 times and even tried another computer with the same result.
You could try flashing an old gingerbread ROM and then try the RUU, as it seems to have something to do with the rom on the phone being newer than the RUU or something.