If you see this error when you (as I have) been innocently downloading a 2 MB attachment from a client - fear not (or fear the worst) as this is the dumb little gmail that is creating a havoc in our lives. Apparently, they have made a mistake in attempting to solve the problem of spammers and have disabled hundreds of accounts. This is what we get in trusting google (the home of the uber-nerds) to be smart enough to not do such mistakes.

This is where you can get the lowdown: Is Your Gmail Account Disabled?

Interestingly, there is no account of this mistake anywhere on their site. Wait till one of the reporters get to suffer from it :)