Just got this email from Google….
You are receiving this message because your email address is associated with an unmigrated legacy Blogger account. As we announced in April of last year, legacy accounts will no longer be accessible after May 30th, 2012 unless they are updated to the Google Account system. Any blog content associated with this account will also be unmodifiable after that date.
To transfer your blog to the Google Account system you need to visit the Legacy Migration page at http://www.google.com/
appserve/mkt/XwhEs5ahHDwakI right now to make sure that your account and associated blogs are claimed. If you’ve forgotten the Blogger password that is associated with this email address, you can use our Account Recovery page at  http://www.google.com/appserve/mkt/k9ak3qH6oHjXeG to request password information to be sent via email.For more information, please see our initial announcement we posted to our blog at http://www.google.com/
appserve/mkt/gk1GnncxkbRzxZ . If you have questions, please visit our Help Forum at http://www.google.com/appserve/mkt/1tkXWGMyAAaToG and create a message with [Legacy Account] in the subject line.
Inasmuch as I don't think affiliates should use Blogger accounts to do business, you'd better migrate / update before you lose your content!