If it's a hotmail, MSN, or Live account, I know of no fix.
You didn't tell if this was a limited account, if so, make it an admin.
So here's the next kink:
I set up a new email account, and checked "Remember Password", but it doesn't remember.
I found a Microsoft article telling me that if my outlook 2000 installation is internet mail only (which apparently it is), I will need to change the registry value for "SMTP Prompt for Password" to 1. This didn't help.
(outlook 2000 / xp sp3)