Re: howto fix corrupted sudoers file?
 

Have you tried "sudo nano /etc/sudoers" as user instead of "sudo gainroot" ?
I doubt it will work but worth a shot. Otherwise, Rob1n's suggestion is your best bet.

You do not need a microSD card since the backup can be stored on the 32gb flash memory.

Shaq

Re: howto fix corrupted sudoers file?
 

@born2wonder

No "sudo nano /etc/sudoers" doesn´t work. I tried with vim, but this shouldn´t make a difference.

That´s right. I had my N900 connected via USB, because of that the backup apps said no microSD card for backup available.
After removing the usb cable the backup is working fine.

I think i´m going to reflash the device, because any other way will take so much time to fix it.

thanks anyone!

Re: howto fix corrupted sudoers file?
 

I have the exact same problem here - but I am quite sure I only installed catorize.
Afterwards the sudoers file was corrupted.
What a pity that I haven't installed sshd server before :-(

Please post here if you have success with reflashing.
Than I'll do the same.

asys3

Re: howto fix corrupted sudoers file?
 

Yes after reflashing (warm) it works like a charm.

You should make a backup of everything before you flash your n900 because afterwards you can restore the backup and nearly everything will be like before.

Re: howto fix corrupted sudoers file?
 

Same thing here, solved it by sshing to the N900 and also running update-sudoers. That fixed it for me.
I also upgraded wizard-mounter, will report it there:
http://talk.maemo.org/showthread.php?t=44188

Best regards,
Corwin