In SharePoint 2010, you may experience this message on your page that you are trying to edit/view:
Important StatusStatus: This page has been declared a record or placed on hold and is locked as read-only

Solution:
1. Ensure that no other users have checked-in the page. You may have to ensure that the page has been Checked-out for you to to edit the page.
2. Ensure you have the appropriate permissions to edit the page.

You may sometimes see this error when creating a new page in a SharePoint MOSS 2007 publishing portal.

“Content type ’0x01010007FF3E057FA8AB4AA42FCB67B453FFC100E214EEE741181F4E9F7ACC43278EE811′ not found in web ‘http://yoururl’

Two step solution:

1. Go to Central Admin, Application Management, User Permissions for Web Application.
Ensure “Use Client Integration Features” and “Use Remote Interfaces” are enabled.

2. Go to Central Admin, Application Management, Policy for Web Application.
Add your user account with Full Control and Finish!

You may have to do an IISRESET and you should be able to create new pages.