System.NullReferenceException Object reference not set to an instance of an object error given when trying to assign a keyboard shortcut.
Go to Tools | Options | Environment | Keyboard | Editor | Execute and select ExecuteSQLStatement. Under Assign keyboard shortcut click ctrl+ E (for example) to assign to keys, but the error is given and nothing is set. This is a problem for any kind of key you try to set.
Waiting for fix in a future version of Toad for SQL Server.