help me unroot i need repair

[1moneymark]

hello all,
i need warrenty repair and need to unroot to return. i rooted using unrevoked. when i run the s-on tool it tells me installation aborted.
E: unsupported radio version
E: update failed. check /sdcard/soff.log
E: error in /sdcard/unrevoked-forever.zip


when i run it again it gets to verifying system type and hangs up. i have to take battery out to reset.
what am i doing wrong.

ive tried to reinistall unrevoked forever and it does the same thing.

my radio is 2.15.00.05.02

is there another way to unroot?
please help

thanks in advance