Lazy Gallery Generating Errors

just tried installing lazy gallery in my site. after it was activated, it started generating strange errors. Now whenever I try logging in it generate 4-5 lines of error code like this.

Warning: Cannot modify header information – headers already sent by (output started at /home/candp/public_html/wordpress/wp-content/plugins/lazy-gallery.php:491) in /home/candp/public_html/wordpress/wp-login.php on line 7

Warning: Cannot modify header information – headers already sent by (output started at /home/candp/public_html/wordpress/wp-content/plugins/lazy-gallery.php:491) in /home/candp/public_html/wordpress/wp-login.php on line 8

Warning: Cannot modify header information – headers already sent by (output started at /home/candp/public_html/wordpress/wp-content/plugins/lazy-gallery.php:491) in /home/candp/public_html/wordpress/wp-login.php on line 9

Warning: Cannot modify header information – headers already sent by (output started at /home/candp/public_html/wordpress/wp-content/plugins/lazy-gallery.php:491) in /home/candp/public_html/wordpress/wp-login.php on line 10

Warning: Cannot modify header information – headers already sent by (output started at /home/candp/public_html/wordpress/wp-content/plugins/lazy-gallery.php:491) in /home/candp/public_html/wordpress/wp-login.php on line 11

Can anybody tell me what the problem is . I am new to wordpress and not much advanced PHP user. Is there any sort of editing/hacks that can solve this?