Thunderbird 3 not connecting with 6.0.5

[freebsdboy]

Trying to get Thunderbird 3 to act as a client to our zimbra 6.0.5 64bit install.
Followed the settings on the wiki(though they are for thunderbird 2) but it acts like the password is incorrect and thunderbird is unable to download messages. (log on to server failed message). I've tried changing the security settings for the account in thunderbird but that doesn't make any difference.
All the zimbra services are running.

Our reasons to using the thunderbird:
Our intentions are to use the webclient for most tasks. However we need a way to do e-mail merges, like merge letters but to email.

The addressing for email merges is not an issue, as they are address in excel from a database.

If there is a better way to do this, I'm all ears.