Hi @sujaselv,
I hope you are well today and thank you for your question.
That error message is generated by Revolution Slider plugin.
Please try deleting and reinstalling Revolution Slider plugin on your site.
Do you have WP_DEBUG set to true in your wp-config.php file?
If you do then please set it to false.
This will hide the warning messages and you will be able to use your site normally.
Best regards,
Shufflehound team