Actually it's not something we could have tested. It's not an excuse, it's an explanation. However, you only sent this 5 hours ago, so I'm not sure how we're providing a "lack of support" here. We're inundated with emails from lots of people, so some patience on your part would be appreciated.
The easy way to fix this is to:
1) Run the Growl uninstaller.
2) Go to launchpad, click and hold Growl there until the icon shakes, and then click the X to remove Growl.
3) Go to the app store and redownload Growl 1.3. It may act like you are buying it, but will then tell you that you have already purchased Growl and will offer to download Growl again for free.
Hope this helps.