I've been receiving a similar error after moving my SSIS project from one machine to another. I now receive the following error:
The component has detected potential metadata corruption during validation.
Error at Data Flow Component [xxxxx]:
System.ServiceModel.Security.MessageSecurityException: The HTTP request is unauthorized with client authentication scheme 'Ntlm'. The authentication header received from the server was 'NTLM'. --->
System.Net.WebException: The remote server return an error: (401) Unauthorized.
at ...
The only difference I see between the client scheme and the server's request is a difference in case between 'Ntlm' and 'NTLM'.
I'm using the 17 Oct 2011 version and have not yet looked into the source code. However, this same package was working with no error on the first machine, but now it is failing when loaded into a different environment.