I'm very sorry to report but this plugin is broken with a 3.0.1 WordPress site.
Me is working on a Mac (latest) with Safari browser (latest) and after i have activate the Live Countdown plugin my browser redirects me to my site's homepage after every click i make.
Doesn't matter.. on what function or button i click in my admin, i will be kicked out of my admin and it ships me to the site's homepage. (in a different browser or TABs)
Yes i did clear my cache files..
I did also double check it in a different browser and Firefox did not had this issue..
I could not check in Chrome because 2 browsers on my computer is more than enough for me :)
But maybe you now have a better view where to look/search for a fix.