it is because the update package in your sdcard is older than your device running right now,
that's why after fre3vo and got root in adb shell (the # sign), you run this command
./misc_version -s 1.31.405.6 , to make your DHD think the update package is newer, and do the update from the IMG file in your sdcard
after update complete (downgrade), you can now use visionary+ to root .
BTW, what's your build number ?
-=[By not using large pic as a signature, you are helping the other save their bandwidth thus reduce global warming]=-
SE k500i<rest in pieces>
-> Nokia 2100<sold>
-> SE k510i<unused>
-> SE w910i<now in my father's hand>
--<BIG LEAP>--> HTC Desire HD <with ARHD roms>
"Since flashing ARHD 6.1.0 now i understand why people really want the sense 3.0 and port them everywhere, because it's really AWESOME"