I may have found the fix here: http://trac.roundcube.net/trac.cgi/ticket/1484074
same here
2006/11/8, Joe Vasquez <joe.vasquez@gmail.com>:
> Is anyone else getting this error?
>
> > DB Error : already exists Query: INSERT INTO messages(...
>
> It's all over my error log. I'm using the latest SVN release.
>
>
> --
> Joe Vasquez
> joe.vasquez@gmail.com
>