Normally, training a single message as good will prevent all future messages from that sender from being classified as spam. The exception is if you are also receiving spam messages from that sender. You can use the Open Log command to see whether (and, if so, why) SpamSieve predicted these messages to be spam. It may be that they are bypassing SpamSieve entirely, e.g. because of a rule on your mail server or in Outlook’s Rules or “Mailing List Manager” window.
Here’s what it says about this message when I use the Open Log command. I don’t know how to interpret:
Trained: Good (Manual)
Subject: 136 New Messages for Fri 10/7 7:00 AM
Identifier: eECq/1gYzlNKUxKEt5F6fA==
Actions: added to Good corpus (5315)
Date: 2011-10-07 06:35:03 -0700
Mistake: False Positive
Subject: 136 New Messages for Fri 10/7 7:00 AM
Identifier: eECq/1gYzlNKUxKEt5F6fA==
Classifier: Encoded HTML
Score: 100
Date: 2011-10-07 06:35:10 -0700
The whitelist didn’t work. So either Use SpamSieve whitelist or Train SpamSieve whitelist is unchecked, or else you’ve trained some of these messages as spam, thus disabling the address on the whitelist. I recommend having both of those options checked.
Since you receive some encoded HTML messages that are not spam, you should uncheck Encoded HTML mail is spam in the preferences.