SMTP Not Receiving Connections

I'm running Windows 2000 SP2 Professional with IIS5.0.
I'm also running the SMTP Virtual Server set to anonymous access allowed.

My problem is that the SMTP doesn't take connections or terminates them "unexpectedly."

I tried testing the SMTP with OE6 with the following result:
Your server has unexceptedly terminated the connection. Possible causes for
this include
server problems, network problems, or a long period of inactivity. Account:
'NONE', Server: 'localhost', Protocol: SMTP, Port: 25, Secure(SSL): No,
Error Number:
0x800CCC0F

The firewall is allowing IIS to go through. Other services on IIS work just fine.

Does anyone have an idea on how I get get SMTP to work and accept connections?

Thanks.

Robert Liao