Have you ever come across the error message “Additions to this website have been blocked” when you are trying to make any changes to a WebSite in SharePoint 2010?
I came across this issue when Upgrading SharePoint 2010 Farm with SP1 and August CU. This necessarily need not be a bug / issue with SP1 / Aug CU.
In Central Admin => Goto Application Managent => Site Collections => Configure Quotas and Locks and make sure Lock status is set to “Not Locked” for the web application having the error.
Hope it helps