Duplicate entry 'themes/garland/garland.info' for key 1 query: INSERT INTO system

Hey Hello.
I was using Drupal 6.13.
In Admin area occasionally i got this error

* user warning: Duplicate entry 'themes/pushbutton/pushbutton.info' for key 1 query: INSERT INTO system (name, owner, info, type, filename, status, throttle, bootstrap) VALUES ('pushbutton', 'themes/engines/phptemplate/phptemplate.engine', 'a:13:{s:4:\"name\";s:10:\"Pushbutton\";s:11:\"description\";s:52:\"Tabled, multi-column theme in blue and orange tones.\";s:7:\"version\";s:4:\"6.14\";s:4:\"core\";s:3:\"6.x\";s:6:\"engine\";s:11:\"phptemplate\";s:7:\"project\";s:6:\"drupal\";s:9:\"datestamp\";s:10:\"1253130027\";s:7:\"regions\";a:5:{s:4:\"left\";s:12:\"Left sidebar\";s:5:\"right\";s:13:\"Right sidebar\";s:7:\"content\";s:7:\"Content\";s:6:\"header\";s:6:\"Header\";s:6:\"footer\";s:6:\"Footer\";}s:8:\"features\";a:10:{i:0;s:20:\"comment_user_picture\";i:1;s:7:\"favicon\";i:2;s:7:\"mission\";i:3;s:4:\"logo\";i:4;s:4:\"name\";i:5;s:17:\"node_user_picture\";i:6;s:6:\"search\";i:7;s:6:\"slogan\";i:8;s:13:\"primary_links\";i:9;s:15:\"secondary_links\";}s:11:\"stylesheets\";a:1:{s:3:\"all\";a:1:{s:9:\"style.css\";s:27:\"themes/pushbutton/style.css\";}}s:7:\"scripts\";a:1:{s:9:\"script.js\";s:27:\"themes/pushbutton/script.js\";}s:10:\"screenshot\";s:32:\"themes/pushbutton/screenshot.png\";s:3:\"php\";s:5:\"4.3.5\";}', 'theme', 'themes/pushbutton/pushbutton.info', 0, 0, 0) in /var/www/vhosts/asd.com/subdomains/ipecs/httpdocs/modules/system/system.module on line 822.
* user warning: Duplicate entry 'themes/garland/minnelli/minnelli.info' for key 1 query: INSERT INTO system (name, owner, info, type, filename, status, throttle, bootstrap) VALUES ('minnelli', 'themes/engines/phptemplate/phptemplate.engine', 'a:14:{s:4:\"name\";s:8:\"Minnelli\";s:11:\"description\";s:56:\"Tableless, recolorable, multi-column, fixed width theme.\";s:7:\"version\";s:4:\"6.14\";s:4:\"core\";s:3:\"6.x\";s:10:\"base theme\";s:7:\"garland\";s:11:\"stylesheets\";a:1:{s:3:\"all\";a:1:{s:12:\"minnelli.css\";s:36:\"themes/garland/minnelli/minnelli.css\";}}s:7:\"project\";s:6:\"drupal\";s:9:\"datestamp\";s:10:\"1253130027\";s:7:\"regions\";a:5:{s:4:\"left\";s:12:\"Left sidebar\";s:5:\"right\";s:13:\"Right sidebar\";s:7:\"content\";s:7:\"Content\";s:6:\"header\";s:6:\"Header\";s:6:\"footer\";s:6:\"Footer\";}s:8:\"features\";a:10:{i:0;s:20:\"comment_user_picture\";i:1;s:7:\"favicon\";i:2;s:7:\"mission\";i:3;s:4:\"logo\";i:4;s:4:\"name\";i:5;s:17:\"node_user_picture\";i:6;s:6:\"search\";i:7;s:6:\"slogan\";i:8;s:13:\"primary_links\";i:9;s:15:\"secondary_links\";}s:7:\"scripts\";a:1:{s:9:\"script.js\";s:33:\"themes/garland/minnelli/script.js\";}s:10:\"screenshot\";s:38:\"themes/garland/minnelli/screenshot.png\";s:3:\"php\";s:5:\"4.3.5\";s:6:\"engine\";s:11:\"phptemplate\";}', 'theme', 'themes/garland/minnelli/minnelli.info', 0, 0, 0) in /var/www/vhosts/asd.com/subdomains/ipecs/httpdocs/modules/system/system.module on line 822.
* user warning: Duplicate entry 'themes/garland/garland.info' for key 1 query: INSERT INTO system (name, owner, info, type, filename, status, throttle, bootstrap) VALUES ('garland', 'themes/engines/phptemplate/phptemplate.engine', 'a:13:{s:4:\"name\";s:7:\"Garland\";s:11:\"description\";s:66:\"Tableless, recolorable, multi-column, fluid width theme (default).\";s:7:\"version\";s:4:\"6.14\";s:4:\"core\";s:3:\"6.x\";s:6:\"engine\";s:11:\"phptemplate\";s:11:\"stylesheets\";a:2:{s:3:\"all\";a:1:{s:9:\"style.css\";s:24:\"themes/garland/style.css\";}s:5:\"print\";a:1:{s:9:\"print.css\";s:24:\"themes/garland/print.css\";}}s:7:\"project\";s:6:\"drupal\";s:9:\"datestamp\";s:10:\"1253130027\";s:7:\"regions\";a:5:{s:4:\"left\";s:12:\"Left sidebar\";s:5:\"right\";s:13:\"Right sidebar\";s:7:\"content\";s:7:\"Content\";s:6:\"header\";s:6:\"Header\";s:6:\"footer\";s:6:\"Footer\";}s:8:\"features\";a:10:{i:0;s:20:\"comment_user_picture\";i:1;s:7:\"favicon\";i:2;s:7:\"mission\";i:3;s:4:\"logo\";i:4;s:4:\"name\";i:5;s:17:\"node_user_picture\";i:6;s:6:\"search\";i:7;s:6:\"slogan\";i:8;s:13:\"primary_links\";i:9;s:15:\"secondary_links\";}s:7:\"scripts\";a:1:{s:9:\"script.js\";s:24:\"themes/garland/script.js\";}s:10:\"screenshot\";s:29:\"themes/garland/screenshot.png\";s:3:\"php\";s:5:\"4.3.5\";}', 'theme', 'themes/garland/garland.info', 0, 0, 0) in /var/www/vhosts/asd.com/subdomains/ipecs/httpdocs/modules/system/system.module on line 822.

Now i have upgraded my drupal to 6.15 and the error does not appear.
Is this a proper solution?
Or can that error may appear again

Thanks Darshan