Hello Mate,
 
1. Please try to check your site again. I resolved it by remove the row – which had ves tabshome widget before.
2. To translate the admin panel. Please try to install the polish language package, and follow the tutorial:
https://github.com/SnowdogApps/Magento-Translation-pl_PL
https://kb.magenting.com/content/14/50/en/translate-magento-interface-magento-localization-tips.html