So just in case anyone runs across this page, here is the fix. This illustrates ones of the major problems with screen scraping: authors change the structure of their content and it ruins your day.
Replace Line 204:
base_snip = re.search(r'window\.GS\.config.+?(\{.+?\});', self.base_html).groups()[0]
With:
base_snip = re.search(r'GS\.config.+?(\{.+?\});', self.base_html).groups()[0]
Notice: the only thing changed was removing "window.". The reason this is happening is that GrooveShark changed the structure of that particular piece of JavaScript so the regex doesn't match anything anymore. The regex searching does not have a "graceful" failure, so it just crashes the whole application without really telling you why: it can't find the string it's looking for!
Have a stupendous day!
PS: emailing the author of this post now in hopes he can update on github