I'm not really sure how you can get this error on a new install of sme 7.0.
Are both of you certain that you have no contribs installed? Did you install, then restore?
Please do - config show horde - Notice the DbPassword setting. Then - pico -w /home/httpd/html/horde/config/conf.php - the DbPassword should match this line - $conf['sql']['password'] =. If not, then signal-event post-upgrade ; signal-event reboot.
HTH,
John Bennett