Too many ambiguities in your post and question. For instance, the 'end' of what? Page? Database? Backup file?
Can you give the exact set of steps and T-SQL, from creating the database to running the commands that do/do not fail? Only then can I explain the behavior you're seeing.
Thanks
Paul Randal
CEO, SQLskills.com: Check out SQLskills online training!
Blog:www.SQLskills.com/blogs/paul Twitter: @PaulRandal
SQL MVP, Microsoft RD, Contributing Editor of TechNet Magazine
Author of DBCC CHECKDB/repair (and other Storage Engine) code of SQL Server 2005