During Exchange Server 2013 setup you may encounter error code 8224 running ldifde.exe to import schema file.
Exchange 2007 ADPrep Error Executing Ldifde.exe to Import Schema File
When you are preparing an Active Directory Forest for Exchange Server 2007 installation you may encounter an ldifde.exe error importing the schema file.
Exchange 2010 FAQ: Is Direct Exchange Migration from 2003 to 2010 Possible Without Upgrading to 2007?
This article explains which upgrade paths are supported from Exchange 2003 to Exchange Server 2010, and under what scenarios you would want to use Exchange 2007 as an interim upgrade path.
Exchange Best Practices Analyzer Reports Unrecognized Exchange Signature
An Exchange Best Practices Analyzer bug gives a misleading error report in scans of Exchange Server 2010 organizations.
Security descriptor error during Exchange Server 2007 schema extension
During Exchange Server 2007 schema extension you may encounter a security descriptor error which will cause setup to fail.