The current implementation only allows very basic website URLs.
Unfortunately not everyone has a top-level domain
For example these URLs are not allowed in the latest version (0.8.3 Beta):
http://www.somesite.com/
http://www.somesite.com/some-url-path/
http://www.somesite.com/some_url_path/index.html
A quick fix for this is to find this string in "functions.php"
/^http{1}s?:{1}\/\/{1}[A-z0-9]+[A-z0-9\-\.]*\.{1}[A-z]{2,4}$/
and replace it with
/^http{1}s?:{1}\/\/{1}[A-z0-9]+[A-z0-9\-\.]*\.{1}[A-z]{2,4}(\/([a-zA-Z0-9\.\-_])+)*(\/){0,1}$/
This will support the URLs above