antystein
Possibly your server has been hacked.
You mention using ftp which is an insecure protocol.
Is the server a web server for web apps eg Wordpress, Joomla etc ?
Have you kept your web apps up to date (particularly anything written using php) ?
Have you kept your server fully up to date with latest packages ?
You do not mention what recent changes you have made, please provide details.
You can insert the install CD for sme 8.0 & boot up your system in Rescue mode.
You should be able to then fix the root password.
Refer to FAQ & Howto documentation for details, links at top of Forum.
If you have been hacked, just fixing the password may not be enough, you need to ascertain how it happened & whether any backdoors have been installed etc.
Usually it's best to Restore from a known good backup from before the hack.
Of course your problem may be something lesser than having been hacked, but we really need to hear a lot more about the history of the server, & what it is you have done in these twice weekly maintenance sessions, in order to help determine how your problem came to be.
eg exactly what changes did you make in the last few days ?
Have you looked at log files ?
You should be able to do this in Rescue mode.