What is the solution to this problem?

I have not resolved the upgrade version

OW Debug - WarningMessage:include(/home/romarekl/public_html/reklamsektor.com/ow_system_plugins/base/components/custom_video.php): failed to open stream: No such file or directoryFile:/home/romarekl/public_html/reklamsektor.com/ow_core/autoload.phpLine:110

Quote from ross If so, then you need to remove the records in the database

Do the search across your database for this component: BASE_CMP_CustomVideo and remove it from every table you find it in.