Does SSPI work?

I am using WinSCP 4.0.4. I was trying to use Kerberos Authentication. I notice there is a GSSAPI/SSPI authentication checkbox. I checked it. However, at the time I checked "Attempt Kerberos 5 GSSAPI/SSPI authentication (SSH-2)" checkbox, it prompts me

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Error
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MIT Kerberos 5 GSSAPI not found. You need to install it before using this feature.
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I ignore it and go ahead to enter username and leave the password field blank. I could successfully logon to my SSH server using Kerberos.

So, my question is "does SSPI support in WinSCP 4.0.4?" If the answer is "yes", why am I prompted to install MIT Kerberos 5 GSSAPI?

I'll send you a debug version soon.

This is has been resolved already. The fix will be included into the next release.