Post Via Email

I want to use one of WP (b2) feature.. the Post Via Email. I think it will be great. I have set the option related to this feature, and when I execute the b2mail.php, I got this:
Ooops POP3: premature NOOP OK, NOT an RFC 1939 Compliant server
What does it mean? Does it mean I can’t run this in my webhost? Or…. anyone uses Post Via Email? Thanks!
PS: WordPress 0.71 rockz! Kewl!