2003 AD 升級到2008 時. adprep32 /domainprep /gpprep 錯誤

請教各位前輩，
目前我這邊的環境如下：
DC1：Windows 2003 Ent 32bit、5大角色 + GC 、DNS
DC2：Windows 2003 Ent 32bit 、DNS
預計新 DC： Windows Server 2008 R2 SP2_X64

我在DC1上面， dcdiag 皆pass ，沒有failed
執行adprep32 /forestprep 已經成功
但執行 adprep32 /domainprep /gpprep 時，卻發生錯誤。訊息如下：
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C:\adprep>adprep32 /domainprep /gpprep
Running domainprep ...

Adprep was unable to create the object CN=Password Settings Container, CN=System,DC=xxxxx,DC=com,DC=tw in Active Directory Domain Services.

[Status/Consequence]
This Adprep operation failed.
[User Action]
Check the log file ADPrep.log in the (null) directory for more information. Restart Adprep.

Adprep encountered an LDAP error.
Error code: 0x10. Server extended error code: 0x57, Server error message: 00000057: LdapErr: DSID-0C
090B38, comment: Error in attribute conversion operation, data 0, vece.

Adprep was unable to update domain information.
[Status/Consequence]
Adprep requires access to existing domain-wide information from the infrastructure master in order to complete this operation.
[User Action]
Check the log file, ADPrep.log, in the C:\WINDOWS\debug\adprep\logs\20130425105025 directory for more information.
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不知道是否有前輩發生過相同的問題 ?
以上請教大家經驗，感謝。