Xp_regread In SQL 2005

I'm having a problem making a call that still works in SQL 2000.



When I call xp_regread, I get the following error:

Msg 22001, Level 16, State 1, Line 0

xp_regread() returned error 5, 'Access is denied.'



My calls work fine when I'm connected normally (either as myself with NT authentication or SQL authentication), but my application is using an application role to provide access to all of the tables and stored procedures. When I set the application role (using sp_setapprole), my call fails. I call a stored procedure in my database, which, in turn, calls master.dbo.xp_regread.



SQL Server is running as Local System.



I don't know what registry permissions I do or don't need in order to get this to work.



Given the error isn't regarding EXECUTE permissions on the procedure, I assume that it is a registry permission issue, not an issue with running the SP.



I found http://support.microsoft.com/kb/887165 related to a similar issue in SQL 2000, but there is no such registry setting when SQL 2005 is installed.



The problem is present in both Vista and WinXP, so operating system doesn't seem to be playing a factor.



I'm creating the Application Role in a SQL2000 compliant manner (EXEC sp_addapprole N'MattAppRole', N'Password123'), and activating it in a similar manner (exec sp_setapprole N'MattAppRole', {ENCRYPT N'Password123'}, 'odbc'). I'm not sure if that matters or not.



If anyone has any ideas what might be causing this problem, I'd really appreciate the help.



Matt