Version:           1.12.1 (using KDE 4.3.0)
OS:                Linux
Installed from:    Ubuntu Packages

When importing "Kmail Maildirs and folder structure" I continually get "Cannot add message to folder Kmail-Import/xxx" pop-up dialog, where xxx is the folders in my current inbox.
In the KmailCVT window, I get "could not import xxx" where xxx is a random collection of numbers and letters which I think is the actual filename where the message is stored.
I copied the entire .kde/share/apps/kmail directory to another location and am using this copy to import. I used tar to dump the entire directory to a file which I then transferred to the new machine via USB stick.
I don't let the import process complete as there are far too many errors.