Before you install SMS you need to extent the active directory schema. to extend it you can follow the steps below

1. user should have the active directory schema rights if not add the user in “SCHEMA admin Group” in DSA.MSC

2. browse the SMS setup CD %cd drive %\smssetup \bin\i386\extadsc.exe from the command prompt and hit enter. your active directory schema will be extended.

*note :- to confirm you can browse through %system Root%\EXTadsch.log