Errors during WHM backup - problem with permissions

Question

Getting this error in our log report for WHM backups.

Copying homedir..../bin/gtar: ./public_html/webmail/SQL: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/config: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/logs: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/program: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/skins: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/temp: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/_old.php.jpgg: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/._CHANGELOG: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/.htaccess: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/CHANGELOG: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/INSTALL: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/LICENSE: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/README: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/UPGRADING: Cannot stat: Permission denied
/bin/gtar: ./public_html/webmail/index.php: Cannot stat: Permission denied
/bin/gtar: Error exit delayed from previous errors

The permissions for webmail looks like this:

drw-rw-rw-  8 mainuser mainuser    4096 Apr 15  2008 webmail

What should it be?