[Dovecot] problem with convert-tool: "Invalid mailbox name"

Hello everyone.

I'm having a problem with convert-tool while trying to convert mbox folders to maildir.

I'm running dovecot-1.1.16 on Centos 5.3

If the user has subfolders, convert-tool fails saying:

"Mailbox conversion: Couldn't create mailbox sub/folder3: Invalid mailbox name"

However, if I ran the convert-tool with the same arguments and same folders with dovecot 1.1.11 on Ubuntu 9.04 it works fine.

Any pointers for troubleshooting this?

Thanks in advance,

Ezequiel