[imp] Problem with folders

[Zlat]

Dear Sir or Madam

I have a question. How can I create a mailbox in some level of folders hierarchy?

For example: I have a folder "INBOX.some-folder" and I want to create a sub-folder named "sub-folder" in it.
But I see an error message such as "The folder "some-folder/sub-folder" was not created. This is what the server said: CREATE failed: Can't create mailbox node /home/z_test/INBOX.some-folder/: File exists".

It is the final step to migrate our corporate system to IMP. Please, help me.
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Sincerely yours,

Victor Kowalenko (Zlat)
web developer and administrator.

E-mail: zlat@mail.od.ua
ICQ: 20072381
SMS: +380677304016