Symptoms:
=======================
You may be unable to run setup /Forestprep and the errors below may be seen. This may happen even with the correct permissions to modify the schema and to the TEMP location. If you review the setup log like the one below, it tells you to consult the LDIF.ERR file but it is never created.

Error Messages:
=======================
"[The component "Microsoft Exchange Forest Preparation" cannot be assigned the action "ForestPrep" because: - Either you do not have permission to update the Active Directory schema or Active Directory service is currently too busy."

Exchange_Server_Setup_Progress.log
--------------------------------------------------------
[09:35:00] ScRunLDIFScript (f:\titanium\admin\src\libs\exsetup\exmisc.cxx:1309)
Error code 0XC1037AE6 (31462): Extending the schema in the Active
Directory failed. Please consult the error log LDIF.ERR in your TEMP directory.
[09:35:00] ScImportActiveDSSchemaChanges
(f:\titanium\admin\src\libs\exsetup\exmisc.cxx:1408)
Error code 0XC1037AE6 (31462): Extending the schema in the Active
Directory failed. Please consult the error log LDIF.ERR in your TEMP directory.
[09:35:00] ScCanUserUpgradeSchema
(f:\titanium\admin\src\libs\exsetup\exmisc.cxx:1623)
Error code 0XC1037AE6 (31462): Extending the schema in the Active
Directory failed. Please consult the error log LDIF.ERR in your TEMP directory.
[09:35:00] - Either you do not have permission to update the Active Directory schema or Active Directory service is currently too busy. -- ID:62081 --
[09:35:00] Prerequisites for Microsoft Exchange Forest Preparation failed: The component "Microsoft Exchange Forest Preparation" cannot be assigned the action "ForestPrep" because:- Either you do not have permission to update the Active Directory schema or Active Directory service is currently too busy.

Application Log:
--------------------------------------------------------
Event ID : 53258
Raw Event ID : 53258
Record Nr. : 1063
Category : SVC
Source : MSDTC
Type : Warning
Generated : 7/25/2007 2:47:14 PM
Written : 7/25/2007 2:47:14 PM
Machine : ServerName
Message : MS DTC could not correctly process a DC Promotion/Demotion event. MS
DTC will continue to function and will use the existing security settings. Error Specifics: d:\nt\com\complus\dtc\dtc\adme\uiname.cpp:9351, Pid: 1496
No Callstack,
CmdLine: C:\WINDOWS\system32\msdtc.exe
Data:
05 ¤

Event ID : 53258
Raw Event ID : 53258
Record Nr. : 1064
Category : SVC
Source : MSDTC
Type : Warning
Generated : 7/25/2007 2:47:14 PM
Written : 7/25/2007 2:47:14 PM
Machine : ServerName
Message : MS DTC could not correctly process a DC Promotion/Demotion event. MSDTC will continue to function and will use the existing security settings. Error
Specifics: %1

Event ID : 4163
Raw Event ID : 4163
Record Nr. : 1065
Category : LOG
Source : MSDTC
Type : Error
Generated : 7/25/2007 2:47:14 PM
Written : 7/25/2007 2:47:14 PM
Machine : ServerName
Message : MSDTC log file not found. After ensuring that all Resource Managers coordinated by MS DTC have no indoubt transactions, please run msdtc -resetlog to create the log file.

Event ID : 4185
Raw Event ID : 4185
Record Nr. : 1066
Category : TM
Source : MSDTC
Type : Error
Generated : 7/25/2007 2:47:14 PM
Written : 7/25/2007 2:47:14 PM
Machine : ServerName
Message : MS DTC Transaction Manager start failed. LogInit returned error
0x5.


Environment:
=========================
Exchange 2000, 2003

Cause:
=========================
This may be caused by problems with MSDTC.

Resolution:
=========================
Verify the Distributed Transaction Coordinator service is started.

If you are getting the 4163 event, run: msdtc -resetlog
If you are getting the 53258 event, you may need to go through Microsoft KB923977

Once the errors above are resolved you should be able to start the MSDTC service and then run /forestprep again.