it seems the post you are referencing tells you most of the solution. Just create an additional partition and install some type of linux distribution on it. When you are installing your desired linux distribution as your main system, change grub or lilo to have a reference to your rescue linux os.
When you experience any problems change your bootoader to boot your rescue partition. Mount your main filesystem in the rescue system and do whatever is needed. When finished change your bootloader back to your main system.
Another possibility is to get access to a remote administration card of the server. The main server producers ship their servers with remote administration cards. IBM calls it RSA, Dell calls it RAC (I think) and HP calls it ILO. With these cards you can remote connect to the console of the server. This way you could choose the booted system from the console or directly do things via remote console.