Two important KB articles have been released recently that relate to the important topic of backup and recovery.
Stsadm can inadvertently delete a root site collection if erroneous URL path used - http://support.microsoft.com/default.aspx/kb/968474
After using stsadm -o restore with the -overwrite parameter and getting an error you notice a site one level up from the site you were trying to restore is deleted. The root level site http://servername is deleted. The site that you were attempting to restore was http://servername/sites/sitename
Microsoft Office SharePoint Server 2007 unsupported scenarios using stsadm -o export /import of subsites - http://support.microsoft.com/kb/968483
In basic terms you cannot use stsadm –o import to restore a sub-site to a root site collection if the publishing feature is enabled, this procedure is generally used to re-organize content.
The supported method to achieve this is to restore is to restore the sub-site to a sub-site within a site collection that has the publishing feature enabled and then copy across any master pages or page layouts that the sub-site relies on to the destination site collection.
Pierre Erol GIRAUDY