Unrecognized disk label on an existing partition table?

[Hong-Siang Teo]

Hi,
I have an existing Linux server (old, slackware 10.1-ish) with two  
partitions, fully bootable and both the ext3 partitions mount fine.  
fdisk recognizes the partition table. The only warning I ever get  
(from fdisk) is that the cylinder >1024, but this has not presented  
any problems for me. The HDD has only ever been partitioned once with  
fdisk. I'm using lilo, placed at the MBR I believe.

Anyway, I want to shift/resize the partitions a bit. So I downloaded,  
compiled, and installed parted 1.8.8. But when I run it, I  
immediately get an error of "unrecognized disk label".

How can I resolve this problem non-destructively? Is there a way to  
add a disk label at this point?

Otherwise, I'm thinking mklabel, then rescue the partitions. But  
there seems to be considerable risks in this maneuver, and I'm not  
sure if it even works.

- Hong-Siang