IMAP Folders that contain Folders

On the most IMAP servers one can create folders that contain other folders,
to get things a bit organised. The main folder that can contain other folders
cannot (in my case) contain any messages.

WLM has a problem with Syncing these folders or even when selected, the
following error appears;

---
Mailbox isn't selectable: Prive

Configuratie:
Account: ****{my name}****
Server: ****{my server}****
Gebruikersnaam: ****{my account name}****
Protocol: IMAP
Poort: 143
Beveiligd(SSL): 0
CODE: 800cccd2
----

Is there a way around this problem, I have multiple IMAP accounts an all
accounts have one or more of these folders that contain sub-folders, with
each sync or send-receive mail command I get a list of errors.

Please help?