Root Unrooting: ERROR [131] CUSTOMER ID ERROR

[JeuneMaya]

I rooted my HTC Desire S using Revolutionary last year. Since I feel that my system is old (with the ICS & latest Sense rolling out), I decided to install the FOTA updates yesterday. It failed, gave me the blue android and exclamation mark image. I read somewhere that it's because the phone is rooted. So I searched online and found this tutorial on YouTube entitled How to S-ON the HTC Desire S, Unroot, remove Revolutionary and Clockwork Mod tutorial by DesireFanatics.... and followed every step.

I'm halfway done, I think. This is what comes up now when I power off and do the press-and-hold volume down and power:

**** LOCKED ****
SAGA PVT SHIP S-ON RL
HBOOT-2.00.0002
RADIO-3822.10.08.04_M
eMMC-boot
Aug 22 2011,15:22:13

Now my failure is in running the RUU file. It gives me ERROR [131] CUSTOMER ID ERROR.

I tried these 3 RUU files but failed each time:
RUU_Saga_H3G_UK_1.31.771.1_Radio_20.28b.30.0805U_38.03.02.14_M_release_178937_signed
RUU_Saga_S_HKCSL_CHT_2.15.832.5_Radio_20.4801.30.0822U_3822.10.08.04_M_release_229399_signed
RUU_Saga_S_HTC_Europe_2.10.401.9_Radio_20.4801.30.0822U_3822.10.08.04_M_release_234765_signed

I even made my SDcard a goldcard, and ran the RUU, but got the same error.

Am I missing something? If it helps, here are some of my software info --
Android version: 2.3.3
HTC Sense: 2.1
Build number 1.31.707.2 CL27073 release-keys
Software number 1.31.707.2


Please help me. I really don't know what to do.
Thank you.