Oh, I've found out that if you edit /usr/sbin/rebuildfstab using KWrite (instead of e.g.vim) it loses its executable status.

You can test for this from the command line by
Code:
ls -l /usr/sbin/rebuildfstab
and restore executability by
Code:
chmod 0755 /usr/sbin/rebuildfstab
(or by right-click on the file in Konqueror, select Properties, Permissions, check "is executable" box).

However, it's still not obvious why your hda1 won't mount . What method are you using to mount ?
e.g. have you tried from the command line
Code:
mount -t ntfs /dev/hda1 /media/hda1
?

e.g.are you using the desk-top icon?

e.g.are you using right-click on the device in KDiskFree ?