I have change all the names of the bx_lucid to bx_lucid_rtl. and i got this error

PHP Fatal error:  Uncaught Error: Call to a member function getLogoParams() on null in /var/www/avren.co.il/a4/studio/classes/BxDolStudioDesign.php:160 Stack trace: #0 /var/www/avren.co.il/a4/studio/classes/BxDolStudioDesign.php(69): BxDolStudioDesign->getObjectDesigner() #1 /var/www/avren.co.il/a4/studio/classes/BxDolStudioDesign.php(60): BxDolStudioDesign->init() #2 /var/www/avren.co.il/a4/studio/design.php(26): BxDolStudioDesign::getObjectInstance('bx_lucid_rtl', '') #3 {main}  thrown in /var/www/avren.co.il/a4/studio/classes/BxDolStudioDesign.php on line 160