The current version of Schupgr.exe cannot be used to upgrade the schema to the Windows Server 2003 forest functional level. ...

The current version of Schupgr.exe cannot be used to upgrade the schema to the Windows Server 2003 forest functional level. To prepare your forest and use the correct version of Schupgr.exe, at the command prompt, type:  adprep.exe /forestprep
 
This operation will incorporate all schema extensions for Windows Server 2003 forest functionality into the upgraded schema. For more information, see the Readme.txt on the Windows Server 2003 operating system compact disc.
 
Schupgr.exe cannot continue.