Tariq, can you please take a look why the rename DDL below does not work:
  EXEC dbo.sp_rename N'[dbo].[dt_addtosourcecontrol_u]', N'dt_addtosourcecontrol_u_new', [OBJECT]
the generated error message is
  Object '[dbo].[dt_addtosourcecontrol_u]' does not exist or is not a valid object for this operation.

In SQL Server 2000 - 54 server, go to fcy_db_test database and expand the 'Stored Procedures' node. The same rename DDL mentioned above works for dbo.fcy_sp_123 but not for dt_addtosourcecontrol_u. Can you please help?

Niels made some changes in UtilScript.java, checked in as SVN #7732 of trunk/ADS, we can deal with 'PROC' keyword now.

dt_stored procedures
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http://databases.aspfaq.com/database/what-are-all-these-dt-stored-procedures-and-can-i-remove-them.html

There are a set of stored procedures that get created when you use various visual tools against SQL Server. For example, this can happen using Visual Studio's Server Explorer to view/create database objects, or something as simple as opening the diagrams node in Enterprise Manager. Even if you haven't created any diagrams, the procedures get created.
 
These stored procedures are used mainly for source code generation, and the dt_ prefix stands for "DaVinci Tools"—an early codename for this technology (but it wasn't fully implemented).

System Stored Procedures -- cannot alter

Enterprise Manager has an option to rename the dt_stored procedures, but I didnt notice the popup which came after I pressed OK which says the Object cannot be Renamed

I spoke to Niels about this issue. We are not going to do any changes for now. I marked this issues Won't Fix.