Are they correct? If not, change them as mentioned above and wait for 1800 seconds. Now, trying redirecting your blog to the custom domain. If they are correct and still you see the problem on the blogger dashboard, then you need to try this...
1. Login to your Google Apps Account - Domain Management. Navigate to "Settings" page from the dashboard. Now, choose sites tab that appears on the left.
2. You will see a tab that shows "Web Mapping". Just click on it. Check whether a mapping exists. If yes, then delete the mapping.
1. Login to your Google Apps Account - Domain Management. Navigate to "Settings" page from the dashboard. Now, choose "Sites" tab that appears on the left.
2. You will see a tab that shows "Web Mapping". Just click on it. Check whether a mapping exists. If not, return to the previous page. Click on "Change URL" link that appears to be blue in color. Have a look at the screen-shot below.
5. If yes, then your problem is solved. Just revert back to the blogspot domain from your blogger dashboard. Save it. Later, login to your Apps Accout and navigate to "Dashboard >> Settings >> Sites". Again hit the "Change URL" link and choose the first option. Save the changes you made. Log out from your Google Apps Account. Wait for few minutes.
6. Now, login to your Blogger Account and try to redirect your custom domain. You will not see "Another blog or Google site is already using this address" error.
Well, if the above two solutions don't work. Then, login to your Google Apps Account and Use the "Support" tab to contact the Google Apps Team. Your query will be addressed in not more than 48 hours. In my case, they even gave me a call to fix the issue. So, don't panic! You will get back your domain! You may contact me via email if you need any help regarding this issue!