Sometimes the ~/*/.kde folder has some corrupt files that I have never been able to find.
Have you tried, just temporarily, rename you ~/*/.kde folder to .kde.bak
Then try it again, maybe relogin.
Haven't setup Kmail for quite awhile, and remember something a little hard at the beginning, but since you have been able to do it as root would think you have that issue in hand.
Possible, not sure. Have you checked if in Mail group. Wouldn't think that would be an issue since can use Mozilla Mail, but never know.
Another issue found with latest Kmail, is when sending email. If get an error about:
[code:1]Sending failed:
Your SMTP server doesn't support authentication.
The server responded: "5.5.1 Command unrecognized: "AUTH PLAIN""
The message will stay in the 'outbox' folder until you either fix the problem (e.g. a broken address) or remove the message from the 'outbox' folder.
The following transport protocol was used:[/code:1]
The fix is: (from jmercer at Gentoo Forums)
[code:1]The problem for me was that my smtp server actually didn't require authentication. I had entered my username and password in both the pop and smtp areas. Try unchecking "server requires authentication" in the smtp section.
The reason that this is a prob in kmail 3.2 and not 3.1 is that 3.1 just ignored this error, 3.2 has decided to complain. [/code:1]
I stopped using Mozilla mail after it would loose my mail at times even though it was still there. I switched over to Kmail and haven't looked back.