Great, hope it is not too difficult to fix.

Just in case it may be relevant, when accessing yahoo mail through the web, I see a Drafts folder. But in my KMail and K-9 Mail clients it is named as Draft (singular). I know it is the same because I can see the draft email I left there with both clients (and the web).

But in SimpleMail, I have an empty Drafts folder. I can see the one from yahoo server when reloading the list from server folders to subscribe, and it also is listed as Draft, but subscribing doesn't work.