CRITICAL_ERROR:
Line 307 /data/web/www.mntgh.abony.hu/class2.php

Error reported as: [3]: Core settings saved - backup made active.

CRITICAL_ERROR:
Line 309 /data/web/www.mntgh.abony.hu/class2.php

Error reported as: [4]: No core backup found. Check that your database has valid content. If not, please run the Reset_Core utility to rebuild your core settings.
After rebuilding your core please save a backup from the admin/sql screen.