Error 15 on boot but using grub command line works with same image!

[Laz]

Hi,

I only really moved over to grub from lilo recently and it had been working 
great. Until now: for some reason, it fails to boot images with an Error 15 
but the images are definitely there and work if I press 'c' and type in the 
same kernel command as is in /boot/grub/menu.lst (tab-completion even 
works!):

Relevant bits of /etc/grub/menu.lst:

title           Debian GNU/Linux, kernel 2.6.13.2
root            (hd2,0)
kernel          /boot/vmlinuz-2.6.13.2 root=/dev/hdc2 ro
savedefault
boot

title           Debian GNU/Linux, kernel 2.6.11.8
root            (hd2,0)
kernel          /boot/vmlinuz-2.6.11.8 root=/dev/hdc2 ro
savedefault
boot

(plus other similar kernels).

$ ls -l /boot/vmlinuz-2.*
-rw-r--r--  1 root root 1331044 2005-05-07 13:31 /boot/vmlinuz-2.6.11.8
-rw-r--r--  1 root root 1387114 2005-10-02 08:51 /boot/vmlinuz-2.6.13.2

This is grub 0.95+cvs20040624-17 on Debian.

Bizarrely, I built a kernel a while back and grub couldn't see that unless I 
put it in the root directory, even though /boot is on the same partition. Now 
it will only boot the rarely used version of windows without having to type 
the kernel bit by hand! The images are on the third IDE hard disk:

$ cat device.map
(hd0)   /dev/hda
(hd1)   /dev/hdb
(hd2)   /dev/hdc

and grub is installed on the mbr of /dev/hda.

It can obviously see the images because it works by hand! I couldn't see 
anything similar to this in the archives, apart from Error 15 meaning that 
the images aren't there but they blatently are!

It does work but requires more human intervention than I'd like!

Any clues for what to check?

Cheers,

Laz