This is now filed as
https://bugs.maemo.org/show_bug.cgi?id=3834 . Any further investigations/comments welcome, as long as it's not "/me too" (we have a Vote feature in Bugzilla for that). :-)

From https://bugs.maemo.org/show_bug.cgi?id=3834 :
Nokia told me that
"We had system clock problem in the Winflasher server hardware. This has been fixed (~today 11:00 GMT+2) and now the Winflasher clients should be working normally."

Can anybody confirm this by adding a comment to the bug report, please?

@ Andre,
I am trying to leave a comment as requested, but I could not find my Bugzilla Acct info. So then I reregistered and now waiting for password. So as frustrated as I am with this I wanted to get the info to you.
I have been dealing with this for 24 hrs. As of 10:00PM GMT (06:00PM EST on 10-30-08 I still have all the issues as described. I have tried everything mentioned previously. One symptom I have that I have not seen mentioned, is that I am being told I have No Internet Connection and I definitely do. I can access http://tablets-dev.nokia.com/ to download without issue. I also cannot do this upgrade manually, it will not let me find a File to select, even when the Option is checked. My File is in the same directory as the Flasher. I would be glad to help out if you need a live case to experiment with. Just let me know

I'm having this problem... I just bought my tablet(n810) and its saying my windows clock is wrong. I've tried hitting back and then next several times with no change. I've tried changing the clock time in windows and that takes me to a new message saying browse for the update on your computer. So I downloaded the update and did it that way but I didnt flash... It just updated in like 30 secs. How Do I Flash ??! LOL I like the device. I'm hating this update wizard...

It usually takes less than 30 seconds to flash it.

then why does the program say it should take 20 min?

That you should ask Nokia

shrug. File a bug :-P

One problem is if the tablet is set to another country or time zone already you have to set your computer to that one aswell. or change tablet. I got a free 770 from Denmark and couldn't reflash it until I booted it up and changed zone on tablet. If you can't boot tablet right now your going to have to change computer.

how do i change the zone? i live in florida so i set the home city to miami when i edit the time i click on miami on the map. is that what you're saying?