Live debug a .NET application, the !mt command just returns "Unable to resolve call target. Error = 0x80004005"

Question

When I break at:

framework.SendEmail(string, string, string, string)

and run !mt I get:

Unable to resolve call target. Error = 0x80004005

What I believe should happen is the debugger should continue, then break at:

smtputil.SendEmail(string, string, string, string)

I'm using sosex.dll v4.5.0.692 on a .NET 2.0 application, with WinDbg 6.3.9600.17298

Any ideas?