I know its not the faulty fstab(I used Installer 1.1a) that is causing this
problem:

When doing a mount -u /(like the FAQ says, I didn't exactly get it, I'm new
to NetBSD and UNIX and should really get a System Administration book) I
get the following reply:

/dev/sd0a on /: specified device does not match mounted device

Can someone help me(again)?