That script doesn't do a heck of alot of checking and usually just works out of the box for me.. it was something is quickly created, then modified due to some other clam alerts i wasn't aware of and then got a little messy.
I've written a PHP version which hopefully will just work on every distro so you just need to make sure you have commands like tar installed.
it's not verbose on the command line at the moment but does the job and sends an email on errors or completion.
give it a try and let me know how you go. I did have some code there which could make the script auto update itself incase of fixes/updates but it's not only not used but i later thought people would worry about it's security so I cancelled going further. It was only going to allow to download and alert to change to the new script (not actually call it ever)..
anyhow, give it a try and let me know of problems. My direct email is in the file.
(remove .txt after download of course