SCVMM Self-Service Portal: “A potentially dangerous Request.Form value was detected from the client”

If you get this error while attempting to log in to the System Center Virtual Machine Manager’s (SCVMM) Self-Service Portal, then you probably have a password that contains “dangerous” characters – for me it was a “<”.  While strong passwords are good to have, they can mess with ASP.NET.  I’d hate to have to be the admin on that domain.  You’d almost have to have a custom password filter DLL that rejected “dangerous” characters from passwords – not to mention a policy for your organization.