Running OpsMgr 2007 R2 DBCreateWizard on 64-bit SQL Server
There is an issue when running the R2 64-bit DBCreateWizard on an SQL server. You may come accross the following error during the DB create process:

Additionally you may see the following in the application log:
Log Name: Application
Source: Bid
Date: 10/14/2009 2:09:38 PM
Event ID: 1
Task Category: None
Level: Warning
Keywords: Classic
User: N/A
Computer: USHUBSPSQL01.Exterran.pvt
Description:
C:\ISO\OpsMgr 2007 R2\DBCreateWizard.exe
8880
Microsoft.EnterpriseManagement.UI.ConsoleFramework, Version=6.0.4900.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35
System.DllNotFoundException: Unable to load DLL ‘MOMBIDldr.dll’: The specified module could not be found. (Exception from HRESULT: 0×8007007E)
at Bid.internalInitialize()
The simple fix is to copy MOMBIDldr.dll from your (hopefully) 64-bit SCOM server to the directory where you copied the SupportTools\AMD64 to and run DBCreateWizard again.
If you are still having issues as I had then check your dbCreateWiz log file from %temp%.
My log file had the following
2:50 PM: CreateDB: Attempting to create OperationsManagerDW on USHUBSQLV14\WHSE_OPSMGR threw the following sql exception Directory lookup for the file “F:\DATA1\OperationsManagerDW.mdf” failed with the operating system error 3(The system cannot find the path specified.).
CREATE DATABASE failed. Some file names listed could not be created. Check related errors..
2:50 PM: Database creation failed. The database might have been incompletely created or modified.
2:50 PM: System.InvalidOperationException: An error occurred while trying to create the database on your SQL Server. Check your logs for more information.
at Microsoft.EnterpriseManagement.Setup.DBCreateWizard.Program.LaunchDBCreation()




