IMAP folders

How do i specify IMAP folders?  My root folder "inbox" works fine.  I've tried 
"inbox/subfoler", "inbox:subfolder", "inbox\subfolder" with no luck.  I just 
get the message:

fetchmail: mailbox selection failed
fetchmail: client/server synchronization error while fetching from 
imap.mymailhost.com

my command has been:
fetchmail -c --folder "inbox/subfolder"

Thanks.

-- 
Michael Lee
Senior Software Engineer
CollegeNET, Inc.