The replacement external USB HDD arrive yesterday. It took a tad long time for UPS to deliver taking into consideration that the package was created on 4th of August! I was expecting just the HDD with the enclosure in the package but WD sent the adaptor, USB cable, and the enclosure support blocks too!
I have the Thinkpad with me till the next couple of days so I though why not start it up with a Knoppix Live CD and partition the HDD using parted. I had the done the same with the earlier HDD. But this time when I committed the changes, it took more than 2 and a half hours for it to write the partition table and inodes on the 90GB partition. I heaved a sigh of relief when it finished. Now all that is left is to copy the configuration files for dirvish vaults and initialize the backups. Keeping my fingers crossed.