After migrating site from SP 2007 to SP 2010 Publishing page ‘Edite Page’ not working

Error:

‘Publishing page’ link not working from path –> http://server/managedpath/sitecollection/_layouts/create.aspx
clicking on ‘Edit Page’ link keep loading and will throw error of ‘Unexpcted error..’ from Ribbon ‘Edit’ Button

Solution:

its fixed now with below solution with changing version number from 12.0… to 14.0….. The problem was with the custom page layout, have changed this for one layout.
@ Page language=”C#” Inherits=”Microsoft.SharePoint.Publishing.PublishingLayoutPage,Microsoft.SharePoint.Publishing,Version=12.0.0.0,Culture=neutral,PublicKeyToken=71e9bce111e9429c” meta:progid=”SharePoint.WebPartPage.Document”

Was changed to

@ Page language=”C#” Inherits=”Microsoft.SharePoint.Publishing.PublishingLayoutPage,Microsoft.SharePoint.Publishing,Version=14.0.0.0,Culture=neutral,PublicKeyToken=71e9bce111e9429c” meta:progid=”SharePoint.WebPartPage.Document”