What problem are you having?
I am unable to add the Active Directory Schema snap-in to Microsoft Management Console (MMC).
Cause: Schmmgmt.dll has not been registered.
Solution: Open a command prompt, type regsvr32 schmmgmt.dll, and then press ENTER.
I am unable to find the Active Directory Schema snap-in.
Cause: You saved the MMC snap-in, but you do not know where it is saved.
Solution: Open MMC (click Start, click Run, type mmc, and then click OK), and then click File. The menu shows the last four locations where you saved a snap-in. Check to see if Active Directory Schema or Schmmgmt.msc is on the list, and then follow the path to the file. When you locate the .msc file, drag it to the Start menu to create a shortcut to the snap-in.